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Trans-Sierra Highways; California State Route 89 over Monitor Pass

Back in 2016 and recently in 2020 I took a circle tour of Sierra Nevada Mountain passes during day trips.  During both of those trips the midway point was California State Route 89 over Monitor Pass. 

The Monitor Pass segment of California State Route 89 ("CA 89") refers to the 17.5 miles of the highway connecting from California State Route 4 in Alpine County east to US Route 395 in Mono County.  Monitor Pass lies at an elevation of 8,314 feet above sea level and is the newest State Highway pass in the Sierra Nevada Mountains. 

Part 1; the history of California State Route 89 over Monitor Pass

The modern route of CA 89 over Monitor Pass traces it's origins back to the Big Trees Road over Ebbetts Pass and the silver boom of Alpine County.  Ebbetts Pass is suspected to have been possibly regularly used by the Miwok and Washoe tribes as a foot path over the Sierra Nevada Mountains.  The 1827 Jedediah Smith Expedition possibly used Ebbetts Pass and what is now Monitor Pass to leave California via Topaz Lake.  Major John Ebbetts claimed to have traversed Ebbetts Pass during April of 1851 with pack mules during the height of the California Gold Rush.  John Ebbetts initially believed that the route he had located would be suitable for a transcontinental railroad but later found it unsuitable when he later returned to survey it.  John Ebbetts intended to return to survey his namesake pass for a wagon road but was killed during the explosion of the steamboat Secretary in San Pablo Bay in 1854.  For the outset the pass discovered by John Ebbetts was referred to by his name although it would not be formally adopted by the U.S. Geological Survey until 1893. 

Ebbetts Pass can be seen on the 1857 Britton & Rey's Road Map of California in what was what Amador County.  Note; the road over Carson Pass can be seen north of Ebbetts Pass in El Dorado County. 

In 1856 an immigrant road was constructed from Murphy's east to Ebbetts Pass.  This early immigrant road diverged from modern CA 4 in Hermit Valley and cut north towards the Carson Pass Road in Hope Valley.  This early route over Ebbetts Pass is depicted in the September 1950 California Highways & Public Works article titled "Crossing the Sierra." 

In 1858 Konigsberg was founded by Norwegian Miners near potential silver claims east of Ebbetts Pass along Silver Creek.  The growth of Konigsberg was spurred by the Comstock Lode Rush out of Nevada by 1859.  Konigsberg’s outward growth spawned nearby communities eastward on Silver Creek and the East Fork Carson River such as; Centerville, Mount Bullion, Monitor (technically on Monitor Creek and modern CA 89), and Markleeville.  The growth around Konigsberg led to a franchise toll road company known as the “Big Tree & Carson Valley Turnpike Company being formed in the winter of 1861-62.   Construction of the "Big Trees Roads" (named after the Calaveras Grove of Redwood Sequoias) over Ebbetts Pass began in June of 1862.  Substantial detail on the construction of the Big Trees Road can be found on sourced from the Alpine County Museum.

The Big Tree & Carson Valley Turnpike entered into a financial agreement with Harvey Blood and Jonathan Curtis of Grizzly Bear Valley in 1864 to pay back taxes which continued to fund construction of the Big Trees Road.  The Big Trees Road was completed to Silver Mountain City by 1864 and largely followed the course of modern CA 4 from what is now Calaveras Big Trees State Park east to Markleeville.  During 1863 the Konigsberg Post Office opened for service and in 1864 the community was renamed to Silver Mountain City.  In 1864 Alpine County was formed and Silver Mountain City was selected as the first Alpine County Seat.  Some sources claim Silver Mountain City reached a population of 3,000 residents by 1866.  In 1868 Blood and Curtis were deeded the Big Trees Road as the Big Tree & Carson Valley Turnpike Company was not generating expected profits.  Silver Mountain City would retain the Alpine County Seat until 1874 when it was moved to Markleeville.  The Big Trees Road can be seen traversing Alpine County by way of Ebbetts Pass on the 1873 Bancroft's Map of California, Arizona, and Nevada.  

At it's peak Alpine County boasted a population of approximately 11,000 residents which was made accessible by way of the Big Trees Road over Ebbetts Pass.  The Mines of Silver Mountain City began to decline in the 1870s and shuttered by 1883.  By 1886 Silver Mountain City had become a ghost town but the franchise rights to the Big Trees Road remained.  The 1889 United States Geological Survey Map of Alpine County shows a connecting road from Mount Bullion on the Big Trees Road east on Monitor Creek to the mining community of Monitor.  Nearby Leviathan Peak can be seen east of Monitor near what would become Monitor Pass.  

Harvey Blood died in 1910 which led to the Big Trees Road being added to the State Highway System as the "Alpine State Highway" under Legislative Chapter:

"The certain road commencing 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 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"

The description above essentially made the Alpine State Highway a discontinuous segment of the already existing Legislative Route 24 ("LRN 24") between Lodi and San Andreas.  This same legislation effectively extended LRN 23 north from Bridgeport over what would come to be known as Monitor Pass to the Lake Tahoe Wagon Road (LRN 11 and the future South Lincoln Highway) in Meyers.  

LRN 23 in it's entirety was promoted as an early Auto Trail known as "El Camino Sierra."  One of the primary goals with the formation of El Camino Sierra was to spur interest in constructing a direct highway route between the Alpine County Seat of Markleeville to the Mono County Seat of Bridgeport.  Travel between Markleeville and Bridgeport required traveling through the State of Nevada. 

El Camino Sierra has origins in the formation of the Inyo Good Roads Club which was founded in April of 1910.  El Camino Sierra was formally dedicated in August of 1910 during a tour of the planned route which was attended by then California Governor James Gillett.  More about the formation of El Camino Sierra can be found on on the History of El Camino Sierra

What would become LRN 23/CA 89 appears as a small connecting road from LRN 24 east to Monitor on the 1917 California State Automobile Association Map

LRN 23 between LRN 24 and the vicinity of Coleville first appears as a proposed highway on the 1918 Division of Highways State Map.  

According to LRN 23 between LRN 24 and the vicinity of Coleville was funded to some degree in 1926.  For reasons unknown it does not appear a route survey was ordered by the Division of Highways.  This unbuilt segment of LRN 23 would be announced as the south terminus of CA 89 ending at CA 7 (future US 395) near Coleville the August 1934 California Highways & Public Works.  

The November/December 1950 California Highways & Public Works discusses the ongoing construction of CA 89/LRN 23 between CA 4/LRN 24 east to US 395/LRN 23.  The article titled "Access to Alpine" discusses the early construction efforts to connect CA 4/LRN 24 east to US 395/LRN 23.  The US Forest Service is cited to have constructed the first half mile west from US 395 into Slinkcard Canyon.  Mono County is cited to have ordered a survey westward 15 miles to CA 4/LRN 24 in 1947 with the initial grading contract being put up for bid in January 1950. 

CA 4 near Ebbetts Pass wasn't connected to US 395 until 1954 when the new extension of CA 89/LRN 23 over Monitor Pass opened to traffic.  The dedication ceremony for the new highway over Monitor Pass is cited to have taken place on September 12th in the September/October 1954 California Highways & Public Works.  The new route over Monitor Pass established the direction connection between the Alpine County Seat of Markleeville and Mono County Seat of Bridgeport that was sought in 1911.

CA 89/LRN 23 over Monitor Pass first appears as a completed highway on the 1955 Division of Highways State Map.  

Part 2; a drive on California State Route 89 over Monitor Pass

My approach to CA 89 towards Monitor Pass in 2016 and 2020 was from CA 4 eastbound over Ebbetts Pass.  CA 4 eastbound terminates at CA 89 at the confluence of Monitor Creek and the East Fork Carson River.  The confluence of Monitor Creek and East Fork Carson River was the location of the town site of Mount Bullion. 

CA 89 southbound begins to climb from CA 4 via Monitor Creek and is signed as "Robert M Jackson Memorial Highway."

CA 89 southbound ascends Loope Canyon to the former town site of Monitor at Postmile ALP 8.199 which was located approximately at the intersection with Loope Canyon Road. Today there isn't much to find of the town of Monitor aside from a clearing alongside the southbound lanes of CA 89. 

According to the town of Monitor was settled in 1862 at the site of the Monitor Mine.  Monitor took it's name from a Civil War Naval vessel.  Monitor drew mostly from the outgrowth of Silver Mountain City but became large enough in 1866 to warrant Post Office Service.  Monitor's Post Office remained in place until 1888 when the community was well past the silver decline of Alpine County.  Unlike Silver Mountain City the community of Monitor managed to limp on for a time after the decline of silver.  Monitor can be seen as it was in this photo sourced from

An answer as to why Monitor didn't disappear like Silver Mountain City appears to be provided by  In addition to silver there was significant claims of; gold, copper, and lead found at the mining claims of the Monitor-Mogul Mining District.  Over twenty mining claims can be seen on in the immediate vicinity of Monitor. 

Monitor was revitalized from east coast investments which led to the Post Office reopening as "Loope" in 1898.  The name "Loope" is taken from the Doctor who organized the east coast investors into revitalizing the community of Monitor.  Loope lingered on until Post Office service shuttered for good in 1908.  Mining around the site of Monitor continued in the form of the Leviathan Mine which can found on northward on Loope Canyon Road.  The Levithan Mine originally opened in 1863 and primarily was used to extract copper sulfate.  A large sulfur deposit was discovered at the Leviathan Mine which led to it's original closure.  

The Leviathan Mine was operated by the Calpine Corporation under sublease from 1935 to 1941 when it shuttered again due to the hazards of underground sulfur mining.  The Anaconda Copper Mining Company purchased the Leviathan Mine in 1951 and converted it to open pit operations from 1953 to 1962.  Alpine Mining Enterprise acquired the Leviathan Mine in 1963 which was subsequently purchased by the State of California.  In 2000 the Leviathan Mine became a Superfund Site and presently remains in the process of reclamation.  

Notably the site of Monitor and Loope Canyon Road can be seen the 1935 Division of Highways Map of Alpine County.  

CA 89 south splits from Monitor Creek at Heehan Lake towards Monitor Pass.  Monitor Pass can be found at 8,314 foot above sea leave approaching the 8,980 foot Leviathan Peak at Postmile ALP 1.87.

South of Monitor Pass CA 89 enters Mono County.  Traffic is advised of 9 miles of downhill grades ahead.   CA 89 at the Mono County line is signed as a Scenic Highway. 

This photo is looking back north towards Alpine County with a guide sign showing Lake Tahoe 48 miles away.

The Great Basin Desert can be seen below from the Mono County Line along CA 89 southbound.  Topaz Lake can be seen from some vantage points. 

CA 89 from Monitor Pass begins to descend and leaves Toyiabe National Forest.  

CA 89 south begins to descend through a series of switchbacks into Slinkard Canyon.  A particular notable vista can be found at Postmile MON 5.248.

CA 89 south descends via 8% grades through Slinkard Canyon and terminates at US 395 near Topaz. 


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