Mormon Emigrant Trail is an approximately 24.5-mile portion of the original routing of the Carson Pass Highway in Eldorado National Forest. Mormon Emigrant Trail begins at California State Route 88 near Alder Hill and extends westward to Eldorado County Route J16 at Sly Park Road.
Carson Pass was a known crossing of the Sierra Nevada by the Washoe and was surveyed in an 1844 expedition led by John C. Fremont. The Carson Pass Highway was plotted as a wagon road by the Mormon Battalion in 1848 and was once the primary crossing of the Sierra Nevada. By the 1880s the Carson Pass Highway had several spurs with the primary traffic corridor being rerouted to Jackson. The original routing towards Placerville would come to be known as Morman Emigrant Trail and became part of Eldorado National Forest in 1910.
Morman Emigrant Trail is part of Forest Road 10N50 and Eldorado National Forest Route 5. Despite being a seasonally maintained roadway corridor Morman Emigrant Trail is occasionally pressed into service as US Route 50 Alternate. During the winter of 1997/1998 large slides closed US Route 50 over Echo Summit. US Route 50 Alternate was commissioned following Sly Park Road on County Route E16, Mormon Emigrant Trail, California State Route 88 and California State Route 89. The designation despite being signed as an alternative it is intended to be used only during emergencies on mainline US Route 50.
Part 1; the history of Mormon Emigrant Trail
Mormon Emigrant Trail is an original component of the Carson Pass Highway and is now maintained by Eldorado National Forest as Forest Road 10N50. Carson Pass Highway crests the Sierra Nevada range at the namesake Carson Pass located at 8,574 feet above sea level. Mormon Emigrant Trail is closed during winters by the Forest Service but occasionally gets pressed into service as US Route 50 Alternate.
What is now Carson Pass was an established crossing of the Sierra Nevada known by the Washoe tribe. During an 1844 expedition led by United States Army Officer John C. Fremont he learned of the pass from the Washoe. Fremont's expedition was encamped at Carson Valley on January 31, 1844, and looking for a way to cross the mountains to return to Sutter's Fort. The Washoe warned Fremont not to attempt to cross the snow-filled pass, but the expedition proceeded regardless. Frontiersman
Kit Carson served as the expedition guide on the journey into the Sierra Nevada.
Fremont's expedition westward to Carson Pass soon ran low on supplies and soldiers soon resorted to consuming their pack animals. On February 14, 1844, Fremont and cartographer Charles Preuss climbed Red Lake Peak where they became the first people of European descent to observe Lake Tahoe. The expedition cleared the snow west of the pass on February 21, 1844, and arrived at Sutter's Fort on March 6th. Despite the harsh wintery conditions, the expedition suffered no fatalities.
John C. Fremont wrote of his experiences crossing the Sierra Nevada which brought attention to what became known as Carson Pass. As the name implies, the pass was named after Kit Carson. Carson Pass became part of the southern branch of the California Trail. Following ill-fated Donner Party expedition of the winter of 1846/1847 the southern leg of the California Trail would see increased usage.
During 1848 former members of the Mormon Battalion who had served in the Mexican-American War opted to return to Salt Lake City. The group of 46 sought to plot a new wagon trail over the Sierra Nevada which incorporated Carson Pass. The expedition departed from the outskirts of Placerville during June up what is now the Mormon Emigrant Trail and would ultimately reach Carson Pass by July 28, 1848. The expedition would successfully cross the Sierra Nevada and reach Salt Lake City by September 1848.
Following the start of the California Gold Rush the Carson Pass Highway would become the favored crossing the Sierra Nevada. Approximately 40,000 gold seekers would cross Carson Pass to the gold mines of the western Sierra Nevada foothills. Carson Pass Highway would remain the favored crossing of the Sierra Nevada until a new routing over Johnson's Pass was established to the north near Lake Bigler (now Lake Tahoe).
In 1853 Congress ordered survey to locate a possible route for a railroad line over the Sierra Nevada range. The conclusion of the 1853 Congressional survey suggested any route over the Sierra Nevada was unfeasibly due to deep snows which occurred every winter. The State of California ordered its own survey by
April 1855 to investigate the feasibility of constructing a wagon road from Sacramento Valley east to Carson Valley.
By June 1855 enough money had been raised so that Sherman Day could scout potential wagon roads over the Sierra Nevada. The Day Survey concluded that the only viable options for a wagon road over the Sierra Nevada would be at Johnson's Pass or Carson Pass. Johnson's Pass was considerable favorable to Carson Pass due to the lower elevation potentially permitting all-year travel. The Day Survey was featured extensively in the September 1950 California Highways & Public Works.
The Goddard Survey later corroborated the findings of the Day Survey in that Johnson's Pass would be the desirable route of a Trans-Sierra Wagon Road.
The surveyed routes of Sherman Day over Johnson's Pass and Carson Pass.
During 1857 the counties of; Yolo, Sacramento and El Dorado contributed $50,000 dollars towards construction of a wagon road over Johnson's Pass. County officials hired noted stagecoach driver J.B. Crandall of the Crandall & Sunderland Company to drive surveyors over Day's route east through the Sierra Nevada range to Carson Valley via Johnson's Pass. The Crandall & Sunderland Company at the time operated as a stage line from the terminus of the Sacramento Valley Railroad in Folsom eastward to Placerville. The stage trip from Folsom originated on June 11, 1857, and proved that a wagon road over Johnson's Pass was indeed feasible.
The Lake Tahoe Wagon Road would be constructed on the Johnson's Pass route between 1858-1865. Following the completion of the Lake Tahoe Wagon Road the Carson Pass Highway would see a decline in usage. The Carson Pass Highway was still close enough to established towns on both ends of the Sierra Nevada that never became fully defunct.
The Carson Pass Highway can be seen originating east of Placerville, California and extending eastward towards Genoa, Nevada on the 1873 Bancroft's map.
By the early 1880s the main line of the Carson Pass Highway was rerouted towards Jackson with a branch to Sutter Creek. The previous mainline west of Carson Pass towards Placerville remained in use as public highway and would come to be eventually known as Mormon Emigrant Trail. The branches of the Carson Pass Highway can be seen in detail on the 1882 Bancroft's map of California and Nevada.
On July 28, 1910, Eldorado National Forest was formally established along the corridor of Mormon Emigrant Trail. In 1911 the California Legislature would commission the Carson Pass Highway east from Jackson to Hope Valley as part of what would become Legislative Route Number 34. The specific wording legislation essentially formed a loop of the Sierra Nevada which included Luther Pass, the conceptual highway over Monitor Pass and the Big Trees Road over Ebbetts Pass:
"The certain road connecting at the Calaveras big tree grove located in Calaveras County thence running to Dorrington in said county, thence E-ly following what is known as the Big Tree and Carson Valley Turnpike to Mt. Bullion in Alpine Cty, thence along the county road to Markleeville in Alpine Cty, thence along that certain road via Kirkwood, Silver Lake, Pine Grove and Irishtown to Jackson in Amador Cty, including therewith the road from Picketts in Hope Valley connecting with the Lake Tahoe Wagon Road, a state highway, at Osgood's Place in El Dorado Cty, and the road from Mt Bullion via Loupe in Alpine Cty to Junction in Mono County connecting with the Sonora and Mono State Highway is hereby declared and established a state highway and shall be designated and known as "Alpine State Highway""
In 1933 the California Legislature extended their portion of the Carson Pass Highway from Hope Valley to the Nevada state line as part of Legislative Route Number 24. The Carson Pass Highway within California would be designated as California State Route 8 when the original run of Sign Routes was announced in the August 1934 California Highways & Public Works. At the time Nevada owned portion of Carson Pass Highway from the state line to Minden was maintained by the Forest Service as the Woodfords Road.
Morman Emigrant Trail can be seen as a minor Forest Service Road on the 1935 Division of Highways map of Eldorado County. Morman Emigrant Trail is shown to originate at California State Route 8 near Alder Hill in Township 9 North, Range 16 East and extending west to Sly Park Road.
By 1940 Carson Pass Highway east of Jackson to the Nevada state line was renumbered as California State Route 88. This can be seen on the 1940 California Division of Highways map.
Originally Morman Emigrant Trail passed through what is now the Jenkinson Lake reservoir where it terminated at Sly Park Road. Sly Park Dam was constructed by the United States Bureau of Reclamation between 1953-1955. This construction required the relocation of Morman Emigrant Trail south of the site of Jenkinson Lake.
In modern times Morman Emigrant Trail is assigned as Forest Road 10N50 and as Eldorado National Forest Route 5. During the winter of 1997/1998 large slides closed US Route 50 over Echo Summit.
US Route 50 Alternate was commissioned following Sly Park Road on County Route E16, Mormon Emigrant Trail, California State Route 88 and California State Route 89. The designation despite being signed as an alternative it is intended to be used only during emergencies on mainline US Route 50.
Caltrans never sought a formal designation of US Route 50 Alternate from the American Association of State Highway Transportation Officials nor assumed maintenance of new roadway segments. Morman Emigrant Trail was repaved and had Postmile paddles affixed with "Route 50A" references to aid the California Highway Patrol. There is no clear evidence that US Route 50 Alternate signage still exists on Sly Park Road.
Part 2; scenes along Morman Emigrant Trail
These photos from March 2026 were taken from the transition from California State Route 88 onto Morman Emigrant Trail. Morman Emigrant Trail crests at 7,415 feet above sea level and was closed at the Iron Mountain Sno Park when these photos were taken.
US Route 50 Alternate signage still exists on Mormon Emigrant Trail. The below photo was taken by Josh Schmid during July 2022.
The same sign as it was during the winter of 2016 (Ray Mullins photo).
This view is along westbound Mormon Emigrant Trail (Josh Schmid photo).
Westbound County Route E16 follows a winding grade through the Sly Park area and intersects Morman Emigrant Trail at Jenkinson Lake. The Jenkinson Lake reservoir is primarily fed by Sly Creek. A highway sign references California State Route 88 being 24 miles away via eastbound Mormon Emigrant Trail.
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