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Frémont 's Route to Carson Pass
an overview and The Key to the Preuss Map
Copyright© September 2000 by Bob Graham

This is intended to be an overview of the entire route from the camp of February 2, 1844 below Markleeville to Carson Pass. Modern placenames will be used throughout. The camp was in the very large grassy area below the town of Markleeville, where Markleeville Creek joins the river. Frémont wrote, "Carson found near, an open hill side, where the wind and sun had melted the snow, leaving exposed sufficient bunch grass for the animals to-night." The view here is looking east. That is Kit at left. This would become the camp where the animals were grazed under charge of Tabeau until February 19th.

Frémont continued, "The nut pines were now giving way to heavy timber.......our elevation above the sea was 6760 feet." The "nut pine," pinus monophyllus, was first collected by Frémont on this expedition.

This determined elevation is way too high. The elevation here is about 5600 feet. Hypsometry was a new science, first applied to surveys in the United States by Frémont 's teacher and mentor Joseph N. Nicollet. Nicollet, himself, was a student of Leplace.
go See the article HYPOSMETRY on this site.

February 3rd. Frémont recorded a move of "7 miles" up Charity Valley Creek to Grovers Hot Springs. All of the distances recorded are, in fact, very close to actual. They passed exposed grassy areas just above Markleeville, but when they arrived here, though this is a meadow, no grass was exposed. The elevation is about 5800 feet, but is much less exposed to the sun and wind. The horses were sent back the 7 miles to the previous camp. The identifying features of the camp at Grovers are the "first appearance" of cedar trees" and the " springs at the foot of a high and steep hill, by which the hollow ascended to another basin in the mountain." First collected by Frémont on this expedition, and cataloged by John Torry, Cedars appear in this photo as the yellow-green foliage.They worked about "a mile or so" further up Charity Valley Creek to where the going gets steep. Indians went by on snowshoes. The view here is to the west, and very top of Markleeville Peak, in full view below, just shows to the left.
go The snowshoes.

East Fork Carson River, September 1855: There is an Indian Tribe [Washo] settled upon [the East Fork of the Carson River] , that from the days of Frémont, appear to have been uniformly friendly to the whites. They bear a high reputation for honesty amonst the inhabitants of Carson Valley. George H. Goddard, Marlette Surveys.

An email from Peter Lathrop of Carson City. Peter has spent years in this area--winter and summer--and has been looking at this part of the route in detail.


Except for the steepest lower parts, the canyon is quite wide, with gentle slopes. There are many shear drop-offs, and the trail travels these slopes to avoid them.

February 4th. They pushed up the canyon, keeping to the side slopes to avoid deeply drifted snow. Frémont records the move as "3 miles," but this particular 3 miles feels like six to me! The climb to Charity Valley is from 5800 feet to 7800 feet in those "3 miles." Adding the "mile or so" of exploration and road preparation of the previous afternoon, makes this move actually about 4 1/2 miles. Details of this portion of the route are given in the next link below, but the camp that night was at the foot of Charity Valley. "Here was a small spot of level ground, protected on one side by the mountain, and on the other by a little ridge of rock. It was an open grove of pines, which assimilated the grandeur of the mountain, being frequently six feet in diameter." 10,000' Markleeville Peak dominates, an andesite cone, and it is grand indeed. The horses at this point had all been moved back to Markleeville. This would be the advance camp until a further move on the 7th.

go For more details on the foregoing, follow a hike from Grovers to Charity Valley.

On February 5th: "While a portion of the camp were occupied in bringing up the baggage to this point, the remainder were busied in making sledges and snowshoes. I had determined to explore the mountain ahead, and the sledges were to be used in transporting the baggage. The mountains here consisted wholly of a white micaceous granite. The day was perfectly clear, and, while the sun was in he sky, warm and pleasant. By observation [at noon] our latitude was 38° 42' 26"; and the elevation by the boiling point, 7,400 feet.

This is The Key to all the travel distances and positions reported between Markleeville and the Pass:

The latitude determined, 38° 42' 26", places the site of the observation further north in Faith Valley than any point appears on either of the maps of the expedition route. This had long been a puzzle to me, and I had thought that it was the latitude for the camp at Markleeville (which, by coincidence, is correct for the grassy hills there), but Frémont recorded that he was in the advance that day at noon - many miles from there. The map referred to here is the foldout detail map of the route from Markleeville to Sutter's inserted between pages 246 and 247 of The Report. Also, there are not enough camps (small circles) for the number of recorded moves. This had puzzled me for 5 years!

To check that the original observation was correct, or recorded correctly, I mathematically created a virtual sun for February 5, 1844.
The solar declinations for 1844 I took from an 1853 edition of Bowditch.
To adjust for longitude, I took the declintions for the 5th and 6th, and made the interpolation for the fact that at noon on the 5th, Frémont, at approximately W120°, was 1/3 of the way into the next day.
I then made the appropriate corrections for parallax, refraction, and the recorded index error of +52 sec (1/2 the values, as an artificial horizon was used), and semidiameter. Dip of the horizon does not apply when using the artificial horizon.
go Artificial horizon
By comparing my virtual sun with the measurements that Fremont recorded, I found his measured altitude of the sun (lower limb--12 double altitudes ranging from 70 02 35 to 70 04 45) to be correct at 35° 02' 22". I then checked that the original reductions were done and recorded correctly yielding N38° 42' 26".
The observation and the determination were correct; he was indeed at N38° 42' 26".
go See the work.

Since, on this leg of the journey, the longitudes are in error due to the failure of his chronometers, in order to get a position fix, it is necessary to come up with a second line of position based on some feature that can be positively identified in the narrative of the report--a river, valley, canyon, or mountain.
Sometimes, as in this particular example, it is usefull that he reported that the mountain was composed of "white micaceous granite," which occurs in this area only on the south and east side of Faith Valley. The rocks on the other sides being either "dark volcanic rock" (andesite) or "very dark volcanic conglomerate ; the lower part s appeared to be of a slaty structure" (metamorphic overlayed with breccia). I then scale these coordinates to topographic maps. Because of the surrounding slopes, the 0bservation of February 5th had to be on the line of latitude 38° 42' 26" in the northeast end of Faith Valley where it crosses the small watercourse that is the headwater of the West Fork of the Carson River. It is difficult to see in the photograph, but this is looking down on a flat, somewhat open area. The white granite clearly shows in the foreground and between the trees.
As noted in the quotation above, the "day was perfectly clear," so Frémont improved upon the weather to make his noon shot with the sextant. The recorded elevation of 7400 feet is very nearly correct. I expect he was looking for an easier route to the Pass pointed out by Mélo by circling the intervening hills, but this proved a dead end. In fact, it would have been necessary to descend into Hope Valley and then back to the pass, adding many miles.This was, then, an exploratory treck, and no milage was recorded in the Table of Miles Traveled in the Report. Frémont did not establish a camp here, and would have returned to the camp established on the 4th at the foot of Charity Valley.

On February 6th, Frémont, Tom Fitzpatrick, Carson, and a small party constructed snowshoes and traveled a reported distance of about 10 miles from the camp to the top of Elephant Back. The distance from the position at the foot of Charity Valley fits. Frémont wrote, "Crossing the open basin, in a march of about ten miles we reached the top of one of the peaks [Elephant Back], to the left of the pass indicated by our guide. Far below us, dimmed by the distance, was a large snowless valley [The Sacramento], bounded on the western side, at a distance of about a hundred miles, by a low range of mountains, which Carson recognized with delight as the mountains bordering the coast. "There," he said, "is the little mountain - it is fifteen [sic] years since I saw it; but I am just as sure as if I had seen it yesterday." Kit recognized the Coast Range from his journey through the San Joaquin and Sacramento Valleys with Ewing Young in 1839. The party then returned the ten miles.

go Mount Diablo--Carson's the little mountain? An examination by Bob Graham and Peter Lathrop.

Thus, in their first days without an Indian guide, February 5th and 6th were both days of exploration for the next moves to the summit.

The next move, on February 7th was a reported 4 miles to the west end of Faith Valley to one of the hills that had grass exposed. Similar explorations of several miles up to the headwaters of Swauger Creek near Bridgeport does not show on the map of the route, nor do the explorations of the 5th and 6th. This seems to be very consistant; apparently, only those moves showing forward progress and actual trail miles were considered as the Expedition route of travel. Frémont wrote, "With one party drawing sleighs loaded with baggage, I advanced to-day about four miles along the trail, and encamped at the first grassy spot, where we expected to bring our horses."
The "grassy spot" is not the meadow, but the hill at left center, and Elephant Back is in the background. The horses were gotten up from Markleeville to this hill by the 15th or 16th.

Notice that on this enlarged section of the Preuss map inserted between pages 246 and 247 of The Report only four circles representing stages on the journey are shown: Markleeville, Grovers, Long Camp, and the Summit at Carson Pass. This represents progress from the 3rd to the 20th of February by the expedition and its animals. A number of intermediate camps, including the camp in Charity Valley of the 4th, 5th and 6th, the camp in west Faith Valley of the 7th and the camp of the 8th and 9th. Several exploratory routes are not shown, including those of the 5th, 6th.
An interesting feature is what appears to be a long body of water where Hope Valley should be. Their view of this was from several miles away on the 14th, when Preuss and Frémont climbed Red Lake Peak. Covered with snow, this very flat valley looks as much like a lake as any of the medium size Sierra Lakes. The expedition would have crossed over the frozen snow-covered Red Lake without noticeing it at all, as the natural lake was a small fraction of its present size as a small reservoir.

"The appearance of Hope Valley indicates it to have been at one period a mountain lake...indeed in the map accompanying Fremont's Report, a lake is represented in this place."

"On a small bench of of the hill below and at the foot of Red Mountain is a small marshy lake, apparently drying up: this is Red Lake, I could not see that it had an outlet, but in all probability it soaks through the narrow rim of white granite rocks that lie on the Hope Valley side."

George H. Goddard, Goddard Wagon Road Survey Report, 1855

Drawn on to a modern aerial map of the area, the route looks like this. I have not shown the route up from Grovers; the camp of the 4th is Charity Valley. The scale is very roughly 1 inch to the mile. The northernmost point, at latitude 38 42 26 is at the bottom of Faith Valley. Frémont may have been looking for an easier approach to the pass, and finding no way arround, moved back to the west end of Faith. The route into Faith Valley to 38° 42' 26" and back does not show as the route of the expedition, nor does the one to Elephant Back.

Below is the route described when made into a three dimentional image using MacDem 68k and POV-Ray software from USGS 7.5" series topographical maps.

February 8th, "Sleighs arrived with baggage about ten o'clock; and leaving a portion of it here, we continued on for a mile and a half, and encamped at the foot of a long hill on this side of the open bottom." This is a further move along the base of Elephant Back in the area of Forestdale Creek. The long hill is likely the one that the animals were brought to on the 19th.

February 10th: "Taplin was sent back with a few men to assist Mr. Fitzpatrick; and continuing on with three sleighs carrying a part of the baggage, we had the satisfaction to encamp within two and a half miles of the head of the hollow, and at the foot of the last mountain ridge. Here two large trees had been set on fire, and in the holes, where the snow had melted away, we found a comfortable camp....The elevation of the camp by the boiling point, is 8,050 feet. We are now 1,000 feet above the level of the South Pass in the Rocky Mountains; and still we are not done ascending. The top of a flat ridge near was bare of snow, and very well sprinkled with bunch-grass, sufficient to pasture the animals two or three days; and this was to be their main point of support. This ridge [Elephant Back] is composed of a compact trap, or basalt of a columnar structure; over the surface are scattered large boulders of porous trap. The hills are in many places entirely covered with small pieces of volcanic rock."
This camp remained the advance camp through the 19th. On the night of the 14th, by the altitude of polaris, Frémont determined the latitude to be N38° 41' 03".

This site, which matches the Preuss drawing, I located in 1996.

go See a comparison

An email from a Long Camp visitor.

This view, looking south across Red Lake shows the campsite and the hill where the horses were grazed.

Frémont's Long Camp is now a Geocache site. Click the Geocaching icon to visit the page.
Anyone with a GPS device can participate in this popular new hobby. There are probably many geocaches right near you. Geocacher LFlood found it: Thank you for your scholarship and efforts to preserve our history. This is a highly deserving cache location. I'm glad it is still in its pristine state.

Feb. 15th: Preuss recorded," Just now we received the news that fifty-one of the remaining sixty-three animals were brought across safely; that is, over the four miles of the path that had been made. Since it was thawing last night, the task was difficult." This four miles would have been from Grovers to the first grassy spot on the west side of Faith Valley (see aerial map below).

Feb 17th: Frémont explored ahead of the pass.
go A view of the route, and an important culinary addition.

Feb. 18th: Preuss recorded, "The horses are now nearby on a snow-free hill, where the grass is said to be rather plentiful." This would be the large hill just northeast of the Long Camp.

Frémont: February 19th - 20th. "On the 19th, the people were occupied in making a road and bringing up the baggage; and, on the afternoon of the next day, February 20, 1844, we encamped, with the animals and all the materiel of the camp, on the summit of the PASS in the dividing ridge, 1,000 miles by our traveled road from the Dalles of the Columbia. The people, who had not yet been to this point, climbed the neighboring peak to enjoy a look at the valley. The temperature of boiling water gave for the elevation of this encampment, 9,338 feet above the sea."

"Thus the Pass in the Sierra Nevada, which so well deserves its name of Snowy mountain [a translation from the Spanish], is eleven degrees west and about four degrees south of the South Pass [of the Rocky Mountains]."

This determination of altitude was too high--the pass today, first opened in 1848 by the Mormon Battalion, is about 8600 feet, but where Frémont crossed was about 9,000'. His determination of latitude at noon on the 19th was 38° 41" 51", the line of which approximates the modern highway at Carson Pass, but he was above the level of the highway. The final assault was a direct route to Red Lake along today's Blue Lakes Road, across frozen snow-covered Red Lake, and then directly up the flanks of Red Lake Peak.

go The 1844 route from Red Lake to the pass, nearly snowless in winter, has been developed by Peter Lathrop.

Red Lake in winter:
"On a small bench of of the hill below and at the foot of Red Mountain is a small marshy lake, apparently drying up: this is Red Lake, I could not see that it had an outlet, but in all probability it soaks through the narrow rim of white granite rocks that lie on the Hope Valley side." George H. Goddard, Wagon Road Survey Report, 1855.

It has often been written that the route of Frémont's expedition crossing was an unfortunate one--that it would have been better to have gone up the Carson River to Carson Pass. Frémont himself thought this in later life and recorded it in his Memoirs.

But I have gained an entirely new insight from hiking the route, and considering the alternatives. I now believe that the route taken, as pointed out by the Indians, was probably the only route that could have been successfully followed in the winter with deep snow with 67 horses and mules.

Frémont was trying to cross with 67 horses and mules in winter--something never previously accomplished, and something never since attempted! Why didn't he just leave the animals and snowshoe across in a few days to Sutter's Fort? The success and objectives of the exploring expedition meant that he had to transport many hundred of pounds of instruments, notebooks and charts, and mineralogical and botanical specimens.

Frémont's comments, "We were obliged to abandon the hollow entirely, and work along the mountain-side, which was very steep, and the snow covered with an icy crust," and "We were often compelled to make large circuits, and ascend the highest and most exposed ridges, in order to avoid snow, which in other places was banked up to a great depth," illustrate the difficulty of getting the animals through the snow. The problem would have been the same up through the Carson Canyon, except that there are no "mountain-sides"--the walls of the Carson Canyon are vertical. This, and other wagon routes, were passable in summer only! Until this era of modern highways, the only traffic through the Carson Canyon in winter was Snowshoe Thompson carrying the mail to Genoa, Nevada on skis.

It is doubtful that there is any other route over which the expedition could have made a successful winter crossing. Thanks to the Indians, they found one.
goSee a cross section of the line of travel.

go In December 1845,Frémont crossed the Sierra by the Truckee route (later Donner Pass), but he didn't follow the emigrant route down the Bear River: his route was that followed by the Central Pacific Railroad in the 1860s and today's Interstate 80. Here for the first time put to a modern map.

go A look at Frémont 's determinations of elevations.
go A look at Frémont 's determinations of coordinates.
go Just who discovered Carson Pass, anyway?
go Finding Frémont 's Long Camp.
go A history of Frémont's training in mathematics, navigation, and mapmaking.
go Follow a hike from Grovers to Charity Valley.
go See the beginning of the route beyond the Pass.

©1999, 2007
Bob Graham