The Lost River Mountains, the Big Lost River Valley, and the Arco Desert of southeastern Idaho

This page offers

digital files of posters about the landscape around Arco,

photographs of the landscape:,
the Headwaters Region I: Copper Basin and the East Fork of the Big Lost River,
the Headwaters Region II:The valley of Summit Creek (the middle fork),
the Headwaters Region III: the North Fork of the Big Lost River,
the northern Big Lost River Valley
the valley of Pass Creek,
the southern Big Lost River Valley
the valley of Antelope Creek,
near Arco,
Arco,
east of Arco: Howe, the Little Lost, and the Lemhis,
southeast from Arco toward the Puzzle,
southeast of Arco: the Big Lost River megaflood,
south of Arco: shield volcanoes,
west of Arco: Timbered Dome & Champagne Creek,
southwest of Arco: Craters of the Moon,
farther southwest: Silver Creek & the Little Wood River,
and even farther southwest: the Big Wood River and beyond.

photographs of the brush on the landscape, and

information about invasive plants in the area, and

essays, and

historic documents.

 






 

There are eight posters about the landscape around Arco. The first five are listed here in a rough geographic order from northwest to southeast, with the fifth just an expansion of the fourth. They are available here for download, and paper copies will soon be offered for sale by the Arco Pretty City Committee.

> > > Poster 1, a sketch of the Lost River Mountains from Willow Creek Summit to Arco. It also has lots of text about the Lost River Range, the Big Lost River Valley, Arco and Mackay, etc.. An early version of this document has hung on the wall at Pickle's for several years. The latest version is available as a pdf and jpeg (an 8087x3635-pixel 16 MB file).

> > > Poster 2, a sketch of a panorama from Craters of the Moon to Arco, looking north to the mountains. It is available as a pdf and jpeg (a 7772x1175-pixel 2 MB file).

> > > Poster 3, a sketch of a panorama looking north from the Twin Buttes and thus at the Lost River, Lemhi, Beaverhead, and Bitterroot mountains. It also has an explanation of their origin. It is available as a pdf and jpeg (a 7772x1720-pixel 4 MB file).

> > > Poster 4, a sketch of the volcanic landscape south of US 20 from Arco to Idaho Falls, with an explanation of its origin that is less long-winded than the one in Poster 5. It is available as a pdf and jpeg (a 7771x1260-pixel 4 MB file).

> > > Poster 5, a sketch of the volcanic landscape south of US 20 from Arco to Idaho Falls, with a more complete explanation of that landscape's origin than the one in Poster 4. It is available as a pdf and jpeg (a 7816x2193-pixel 7 MB file).

 > > > Poster 6 showing the geologic history of Lost Rivers, Lemhis, and Beaverheads. It has the series of cross-sections also shown on Posters 1 and 3 and a three-dimensional sketch unique to Poster 6. It is available as a pdf and jpeg (a 1700x2409-pixel 2 MB file).

> > > Poster 7, a profile of a borehole drilled in the Snake River Plain and thus about the rocks underlying the Snake River Plain south of Arco. It is available as a pdf and jpeg (a 2114x2806-pixel 2 MB file).

> > > Poster 8, a block diagram putting in context the outcrops, boreholes, and excavations where the relationship of basalt and rhyolite of the Snake River Plain can be seen. It is available as a pdf and jpeg (a 3300x2050-pixel 3 MB file).

 

There are also larger documents with combinations of Posters 2 to 5. For someone printing the posters, these Combo-Posters may be an efficient option.

> > > Combo-Poster 1, which combines Posters 2, 3, and 4. It is available as a pdf and jpeg (a 7840x4200-pixel 9.8 MB file)

> > > Combo-Poster 2, which combines Posters 3 and 5. It is available as a pdf and jpeg (a 7820x4119-pixel 11.2 MB file)

 






 

Photographs of the landscape in the Big Lost River Valley and the Arco Desert, in very rough order from north to south.  Unless otherwise noted, all images are less than 5 MB. There is also a base map labeling some of the places mentioned.

There are many pictures here; some favorites are marked with -o)+(o- .

 

In the headwaters region, Part I: Copper Basin and the East Fork of the Big Lost River

The peaks of the Wildhorse Creek drainage and Copper Basin seen from the flanks of Borah.

The Swamp, the headwaters of the East Fork, under the White Knobs.

The meandering East Fork below its confluence with Cabin Creek.

A view west from the Burma Road across Copper Basin to Standhope Peak.

Three views of glacially sculpted valleys in western Copper Basin.

The tree-lined northwest-flowing East Fork of the Big Lost River in Copper Basin.

An apparent fault scarp on the east side of the East Fork, near the mouth of Copper Basin .

 

In the headwaters region, Part II: the valley of Summit Creek (the middle fork of the Big Lost River)

A view looking across the North Fork and up the valley of Summit Creek (i.e., up Trail Creek Road).

A view looking downstream at terraces of sediments in the valley of Summit Creek.

A view looking west across Summit Creek at Devil's Bedstead.

A view looking upstream in the valley of Summit Creek (i.e., up Trail Creek Road).

Summit Creek (a.k.a. the Lost River) on an 1897 map.

 

In the headwaters region, Part III: the North Fork of the Big Lost River

Cirques and horns at the upper end of valley of the North Fork.

One of those cirques.

A view up the North Fork canyon at Ryan Peak in the Boulder Mountains.

A view farther up the North Fork canyon at peaks in the Boulder Mountains.

A beaver pond in the North Fork.

A view looking downstream at an un-dammed section of the North Fork.

A meander of the North Fork.

 

Local residents near the confluence of the North Fork and East Fork.

The confluence of the North Fork and East Fork.

 

In the northern Big Lost River Valley:

A view from above Willow Creek Summit in 2019: the Lost Rivers, White Knobs, and Pioneers.

The Chilly Buttes and the northeast-flowing stretch of the Big Lost River.

The White Knobs and the Pioneer Mountains seen from Willow Creek Summit in 2011.

The northern Lost River Mountains from Willow Creek Summit in 2011.

Dickey Peak in the northernmost Lost River Mountains, seen from the Doublesprings Pass Road.

Borah Peak in the northern Lost River Mountains, seen from Corral Creek Summit .

-o)+(o- The view west from Double Springs Pass of the Chilly Buttes and the Pioneer Mountains.

Dickey Peak in the northernmost Lost River Mountains seen from the Borah Trail.

The Chilly Buttes.

-o)+(o- The northern Lost River Mountains seen from the old bridge to the Fish Hatchery in 2016, before the new bridge.

The northern Lost River Mountains seen from the Burma Road.

A view down the Borah Peak Trail.

Leatherman Peak, Badrock Peak, and Mount Church in the northern Lost River Mountains.

Mt. McCaleb seen from the mining district above Mackay.

Mt. McCaleb, lightly dusted with snow.

The White Knob Mountains seen from across the valley

The White Knob Mountains seen from four directions

Leslie Butte.

The northern Lost River Mountains in snow in January 2016. Pass Creek is at the far right.

 

The valley of Pass Creek:

Layers of limestone in the Pass Creek Narrows.

-o)+(o- The view looking west from Blacktail Summit of Mud Lake and the Pass Creek Narrows.

The view from Blacktail Summit looking west over the Pass Creek Narrows into the valley of the Big Lost River.

The canyon of Methodist Creek.

-o)+(o- Pass Creek looking west from the summit to the narrows and on across the valley of the Big Lost River.

Pass Creek looking west from above the summit to the narrows and on across the valley of the Big Lost River.

 

In the southern Big Lost River valley:

A wall of sandstone in Elbow Canyon. This wall consists of vertical layers that were horizontal when deposited.

A view out of Elbow Canyon over the valley of the Big Lost River to Sheep Mountain .

The southern Lost River Mountains seen from Alder Creek in summer 2016.

-o)+(o- The southern Lost River Mountains seen from Alder Creek in November 2014.

Shelly Peak from Alder Creek.

Shelly Peak seen in snow from Houston Road in November 2014.

Challis volcanics, Shelly, and Redbud seen from Alder Creek.

-o)+(o- The landslide in Ramshorn Canyon and the meadow that has formed upstream from it.

The view from Ramshorn Canyon across the Big Lost River Valley, with Smiley Mountain on the horizon at the right.

Sheep Mountain from Alder Creek (from the north).

King Mountain seen from the eastern (Little Lost) side.

The Big Lost River Valley seen from Beverland Pass in 2009.

Appendicitis Hill in morning light.

 

The valley of Antelope Creek:

Scenery low in the valley of Antelope Creek.

Limestone outcrops in the valley of Antelope Creek.

Shelly Peak and two volcanic prominences in Antelope.

Shelly Peak from the south side of Antelope.

The Winged Nike of Waddoups.

Sheep Mountain from the southeast (as commonly approached on the Waddoups Canyon Road).

Sheep Mountain from the south.

Shelly and Sheep from the south.

Smiley Mountain and the meadow of Antelope Valley .

Smiley Mountain from Mountain Spring.

The canyon of Bear Creek from Antelope.

Sheep Mountain and Black Cap Peak in Antelope.

The canyon of the Dry Fork of Antelope Creek.

Scorpion Mountain from Antelope.

The canyon of Iron Bog Creek.

 

Near Arco:

A vestige of the Lost River Highway.

-o)+(o- The Big Lost River Valley and the northern Big Lost River Mountains seen from Arco Peak in 2012.

A view west from Arco Peak to Sheep, Shelly, Redbird, and White Knob, unlabeled and labeled.

The Lost River Lava Flow (an 7MB multi-image jpeg).

The north vent of the Lost River Lava Flow seen from the south vent.

The excavation on Sunset Drive / Aikele Road / 2500N: images and geological inference (an 11MB jpeg).

Number Hill from the side and a snowy Smiley Mountain in June 2017.

Number Hill in snow.

Features of the limestones of Number Hill and the southern Lost River Mountains.

Smiley Mountain (in the center) and other peaks from Number Hill.

-o)+(o- A sunrise view from Number Hill of the Big Lost River Valley and Smiley Mountain in July 2017.

The B from the top of Number Hill . Both the B and the pointed top of Arco Peak are visible to the upper right.

The east side of Number Hill.

Shelly Peak, the White Knobs, and Sheep Mountain seen from south of Arco.

The Big Butte seen from the canyon behind Number Hill.

The Big Butte from above the A.

 

Arco itself

Arco and the southern Lost River Mountains.

Arco and the landscape to the south and west.

Arco and Number Hill seen from the B in 2017.

Arco seen from Number Hill in 2011.

A more detailed view of Arco from Number Hill in 2012.

Arco seen from above the A in 2019 .

Arco in a more detailed view from above the A in 2019 .

Smoke from the Sheep Fire arriving in Arco in 2019.

The sail of the USS Hawkbill.

The Atomic Days ping-pong-ball-drop of 2014.

Rain over Arco on June 9, 2019.

 

East of Arco: Arco Pass, Howe, the Little Lost, and the Lemhis:

A view west from Arco Pass into the valley of Godfrey's Ranch.

Lost businesses of Howe.

A roundup in Wet Creek.

Hawley Mountain and the Hawley Mountains.

A traveller's resting spot on the Little Lost Highway.

Eroded terraces in the Little Lost, and the Lemhis.

Warm Spring Creek in the Little Lost.

A view east from above Pass Creek Summit to Bell Mountain in the Lemhis.

Bell Mountain, the Little Lost, and the Lemhis.

Diamond Peak in the Lemhis and Badger Creek in the Little Lost.

A panorama of the Lemhis: Bell-Diamond-Tyler-Saddle.

Diamond Peak from the east (Birch Creek) side.

The Little Lost and the Lemhis seen from Arco Pass.

Saddle Mountain in the Lemhis from the west, southwest, south, and east.

Rhyolite at Howe Point.

 

Going southeast from Arco to the Puzzle and the Twin Buttes:

Tea Kettle (or Teakettle) Butte seen from the northeast.

Ponds made by the Big Lost River near the Big Butte during the wet early June of 2018.

Crater Butte east of Butte City and over which US Highway 20/26 passes.

The lower (Powell) dam of the Big Lost River downstream from Arco.

A view looking north from the Big Butte's northern canyon.

The Big Butte seen from the west. Note the alluvial fan at the base of canyon seen in the image above.

Cedar Butte (left) and the lesser Cedar Buttelets seen from the north-northeast.

Cedar Butte itself.

The summit of Cedar Butte.

The view looking north from Cedar Butte toward the lesser Cedar Buttelets.

The Big Butte seen from the top of Cedar Butte.

The view from Cedar Butte of the cedars that give it its name, the Cerro Grande Lava Field, and the Twin Buttes in the distance.

The view looking southeast from Cedar Butte over the Cerro Grande Lava Field.

Cerro Grande from Cerro Grande.

The last vestige of Cerro Grande.

A basalt wall in the desert.

The railroad cut through a lava flow between Atomic City and Cedar Butte.

Table Legs Butte from the east.

Table Legs Butte from the top of the southeast "leg".

The Puzzle.

The Twin Buttes seen from US 20, as seen by every traveler.

The three buttes of the Twin Buttes (really!).

 

Southeast from Arco: The Box Canyon of the Big Lost River

-o)+(o- The Big Lost River approaching the Box Canyon.

The Big Lost River entering the Box Canyon.

Columnar basalt seen from the side in the Box Canyon.

Columnar basalt seen from the top on the flanks of the Box Canyon.

The Big Lost River in the Box Canyon, as seen looking upstream from the west bank.

An instructive view looking upstream in the Box Canyon from the east bank in the wet summer of 2017.

\-(o)-(o)-/ An aesthetic view looking upstream in the Box Canyon from the east bank in the wet summer of 2017.

A view looking downstream in the Box Canyon from the east bank toward the Big Butte in the wet summer of 2017.

 

Southeast from Arco: the Big Lost River megaflood

The Big Lost River megaflood 22,000 years ago.

The 2800W erratic.

Another erratic.

A basalt boulder.

A cataract left by the Big Lost River megaflood, seen from downstream.

A different cataract left by the Big Lost River megaflood, seen from the side.

 

Going south from Arco: shield volcanoes

Sixmile Butte and Wildhorse Butte seen from between Arco and Butte City.

Sixmile Butte and Wildhorse Butte seen from the Mountain-Man bend on US20/26/93.

The buttes of the Arco desert, seen from the southern vent of the Lost River Lava Flow.

A map of the buttes, and of the lava flows that spread from them (a 7 MB file).

Arco Peak, King Mountain, and the westernmost ridge of the Arco Hills from Goodale's Cutoff .

Flat-topped Sixmile Butte, seen from the Arco-Serviceberry Road.

The basalt pavement of the surface of Sixmile Butte, and the view toward King Mountain and Arco at the far left.

A less instructive but more aesthetic view from Sixmile Butte toward Arco Peak and King Mountain.

The north side of Sixmile Butte.

The top of Wildhorse Butte in 2018.

-o)+(o- The view from Wildhorse Butte of Pass Creek, the southern Lost Rivers, Arco, King Mountain, peaks in the Lemhis, and the Arco Hills.

Huddle's Hole (a kipuka) seen in the mid-right distance from Wildhorse Butte.

Huddle's Hole (a kipuka) seen from its northern entrance.

Wildhorse Butte from the south - not scenic, but informative.

A view of Fingers Butte showing why it's called "Fingers Butte".

-o)+(o- A view looking northwest from Quaking Aspen Butte at Fingers Butte and other prominences.

Quaking Aspen Butte seen from the north.

Quaking Aspen Butte seen from the west.

The cairn atop Quaking Aspen Butte and the view to the west.

The north side of Quaking Aspen Butte in the wet summer of 2017.

The Big Butte seen from the south, from near Cox's Well.

The Cox's Well Landing Strip.

A view looking north from south of Cox's Well.

 

West of Arco:

Timbered Dome, Scorpion Peak, and Smiley Mountain seen from Arco.

Timbered Dome on July 1, 2016, three days before the fire, as seen from Bathtub Hill east of Arco.

Timbered Dome from the south in 2018.

Timbered Dome from the west in 2019.

A roadcut of rhyolite near the mouth of Champagne Creek.

An old structure in the canyon of Champagne Creek.

The Last Chance Mine in the canyon of Champagne Creek.

The view from Champagne Creek Summit.

The last vestiges of the town of Martin.

 

Southwest of Arco: Craters of the Moon

Southwest of Arco is Craters of the Moon, officially represented by the National Park Service's Craters of the Moon website.

A view of the Craters' Blue Dragon lava flow from the air.

A view of COTM from the flank of Quaking Aspen Butte, looking over lichens on basalt.

An eruptive cone at Craters, with Laidlaw Butte on the horizon.

Indian Cave at Craters in 2010.

Dewdrop Cave at Craters in 2010.

The Big Butte seen from a snowy Craters of the Moon in January 2016.

Colorful expanses of cinders at Craters, and Timbered Dome in the distance.

Inferno cone (at lower right) and the Pioneer Mountains in snow and clouds on June 1, 2019.

Big Cinder Butte, COTM's highest and largest feature, seen
(1) from the north,
(2) from the southeast, and
(3) from above Arco in July 2018.
In 2 and 3, note the Butte's left wing, which makes it identifiable from a distance.

Molds of tree stumps southeast of Big Cinder Butte.

 

Farther southwest: Picabo, Silver Creek, and the Little Wood River

Outcrops of basalt and rhyolite south of Picabo.

Silver Creek cutting through basalt south of Picabo and Carey.

Silver Creek cutting through basalt farther south of Picabo and Carey.

\-o)+(o- A view looking from Preacher Bridge upstream toward the mountains.

A view looking from Preacher Bridge downstream toward the desert.

An old railroad bridge over the Little Wood River.

A view looking from Pangari Bridge upstream toward the mountains.

A view looking from Pangari Bridge downstream toward the desert.

 

Still farther southwest: the Big Wood River and beyond

The Big Wood River cutting through basalt near Sheep Bridge between Picabo and Fairfield.

The Big Wood River sculpting basalt in the Black Magic Canyon.

The Big Wood River's slot canyon in the Black Magic Canyon.

Pillar Falls, Shoshone Falls, and Twin Falls of the Snake River.

The unconformity of basalt on "rhyolite" at Shoshone Falls.

 






 

Photographs of land-covering plants and brush covering the landscape around Arco, in order of size from shortest to tallest, with asterisks marking the two that are most common:

Halogeton or saltbush.

Winterfat.

Antlelope bitterbush.

Green rabbitbrush.*

Gray rabbitbrush.

Green and gray rabbitbrush side-by-side.

Fernbush or Desert Sweet or Tansy.

Sagebrush.*      . . . and a note about four-lobed sagebrush leaves

Mountain Mahogany.

              . . . and a note about the size of dryland leaves.

 






 

Photographs and descriptions of invasive plants:   The documents linked here come from the website of Invasive Species of Idaho and specifically from https://invasivespecies.idaho.gov/terrestrial-plants.

These invasive species have been categorized by the state as
(1) Weeds to be eradicated during the same growing season as the season in which they are identified (i.e., immediately);
(2) Weeds to be controlled or eradicated;
(3) Weeds to be contained to prevent new or expanding populations.

Invasive plants reported from Butte and/or Custer Counties:
    Black Henbane 2
    Dyer's Woad 2
    Japanese Knotweed 2
    Matgrass 2
    Perennial Sowthistle 2
    Plumeless_Thistle 2
    Russian Knapweed 2
    Canada Thistle 3
    Dalmatian Toadflax 3
    Diffuse Knapweed 3
    Field Bindweed 3
    Hoary Alyssum 3
    Houndstongue 3
    Leafy Spurge 3
    Oxeye Daisy 3
    Perennial Pepperweed 3
    Poison Hemlock 3
    Puncturevine 3
    Purple Loosestrife 3
    Rush Skeletonweed 3
    Saltcedar or Tamarisk 3
    Scotch Thistle 3
    Spotted Knapweed 3
    Tansy Ragwort 3
    White Bryony 3
    Whitetop 3
    Yellow Toadflax 3

Other invasive plants reported from counties adjacent to Butte and/or Custer Counties:
    Bohemian Knotweed 2
    Buffalobur 2
    Johnsongrass 2
    Mediterranean Sage 2
    Orange Hawkweed 2
    Small Bugloss 2
    Vipers Bugloss 2
    Jointed Goatgrass 3
    Yellow Starthistle 3






 

Essays and documents made recently:

A geologist's view of the region around Arco.

Alexander Ross and Thyery Goddin in the Lost Rivers country in 1824.

A short history of Arco.

Changing flow of the Big Lost River.

A plot of the populations of Arco, Mackay, and Butte County through time

Patterns in vehicular traffic through Arco.

 






 

Historic documents:

1881 list of Idaho Post Offices in the Official Register of the United States.

1884 list of Idaho post offices in Polk's Gazetteer.

A section about the Lost River Valley(s) in an 1884 History of the Idaho Territory.

Snippets about Arco, Howe, Martin, etc. in Polk's Idaho Gazetteer for 1884.

An early photograph of a train in Arco.

Evidence that the railroad passing through Arco was called the Salmon River Railroad and was expected to go to Challis.

1909 ads for the Big Lost River irrigation project.

a 1913 letter to the Governor about the Big Lost River irrigation project (a 23 MB pdf file).

A report on the irrigation schemes of 1906-1918.

A rosy 1917 article about Arco.

A 1937 tour from Blackfoot to Arco to Mackay to Challis.

Maps:

An 1812 map of the region.

An 1837 map of the region.

A recent map of trails.

An 1881 map of trails and railroads.

An 1884 map of trails and railroads.

A 1901 map of railroads.

A 1911 map of railroads.

A 1920 map of railroads.

A 1920 map of railroads and power lines.

A 1927 map of highways.

A 1930 map of railroads.

A 1937 map of highways.

A 1939 map of Idaho Route 22 through Martin.

A 1942 map of railroads.

A 1956 map of highways.

A 1958 map of railroads and highways.

A 2015 map of highways.

A 1902 timetable for the Oregon Short Line showing desert stops at Cerro Grande and Powell.

A 1938 timetable for the Union Pacific showing desert stops at Furey, Cerro Grande, and Pioneer,
and valley stops at Lost River, Moore, Darlington, Leslie, and Rothas.

A 1944 timetable for the Union Pacific showing a desert stop at Scoville.

A 1961 timetable for the Union Pacific, the last timetable for passenger service to Arco.

A 1973 timetable for the Union Pacific showing freight service to Arco.

 






Errors and problems should be directed to rlsbk@gly.uga.edu.

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