Which Mountain Did Fremont Climb?
In August 1842 Lt. John C. Frémont led an Army Topographical Mapping Expedition over South Pass in central Wyoming. He then turned to the northwest and proceeded along the western side of the Wind River Mountain Range. After leaving some of his expedition at a base camp near today’s Boulder Lake, he headed into the mountains to climb the highest peak. On reaching the summit on August 15, 1842, he declared:
We had accomplished an object of laudable ambition, and beyond the strict order of our instructions. We had climbed the loftiest peak of the Rocky mountains, and looked down on the snow a thousand feet below; and, standing where never human foot had stood, felt the exultation of first explorers.
Which peak Fremont climbed has been a source of speculation ever since. Most historians assumed that Fremont climbed Fremont Peak. In 1960, Orrin Bonney, a prominent mountaineer in the Wind River Mountains, made a strong case that Fremont had climbed Mount Woodrow Wilson. Other peaks have been suggested at various times, but Fremont Peak and Mount Woodrow Wilson remain the two prime candidates.
This question can finally be answered with a high degree of certainty. Fremont took a number of barometric pressure measurements during his trip into the Wind River Mountains. These measurements can be converted into estimated elevations and associated error using a modern atmospheric pressure model. These measurements show that with a probability >99%, Fremont was standing on the summit of Fremont Peak on the afternoon of August 15th 1842.
A secondary calculation was done using only Fremont's barometric measurements on August 15th . This method shows that the elevation of Fremont's summit was 3,297' above his campsite at Island Lake. Since Fremont's campsite is located at 10,442', this yields an elevation at the summit of 13,739'. The actual elevation of Fremont Peak is 13,745'. The elevation of Mount Woodrow Wilson is 13,502'.
All of Fremont's barometric pressure measurements in the Wind River Mountains, excepts from Fremont's 1842 Expedition Report, excerpts from the Charles Preuss diary, and a full explanation of the elevation analysis is explained in Which Mountain Did Fremont Climb .
John Grebenkemper
November 27, 2004