First established as a rich placer camp in early 1850, the town's later importance came from the fact that it was located on the rich quartz veins of the Mother Lode. This allowed the camp to survive even after the placers were worked out and gave the town an extended lease on existence.
Known originally as La Mineta, Spanish for "little mine," the camp's name was later changed to Princeton, after the nearby Princeton Mine which opened in 1852. Eventually reaching a vertical depth of 1,350 feet, the mine produced close to $5 million in gold during its operation, making it the largest gold producer in Mariposa county.
The mountain to the north of the town was named "Mount Bullion" after the death of Frémont's father-in-law, Senator Thomas Hart Benton, whose unconditional stand favoring hard money - gold and silver coins - earned him the sobriquet "Old Bullion" from his congressional counterparts. When the post office was established on July 10th of 1862, it was given the name Mount Bullion and while mail was addressed to that name, the town was still known as Princeton. When the Princeton Mine finally closed, the name Mount Bullion became more generally accepted and soon claimed title to the town.
Mount Bullion was also an important supply center for the placer miners whose workings - piles and piles of stones - can be seen along almost every creek and stream in the area. Combined with the large number of men working at the quartz mines, Mount Bullion was quite a substantial community during the early years. Along with the many tents, cabins, stores, and saloons, the town boasted a large, two-story hotel, an ice cream parlor and a schoolhouse second to none in the county.
Today Mount Bullion is a quiet collection of homes and ranches spread out along the west side of Hwy 49. Although no buildings are left from Gold Rush times, a drive through the streets of this old mining camp can still impart a sense of what it must have been like during those days when a fortune could be made overnight, and lost just as quickly at the nearest saloon or fandango.
Frémont Peak, the site of "Camp Jessie," is the highest point of elevation on the long, massive ridge known as Mount Bullion. It tops out at 4,199 feet of elevation, and after hiking to the top, climbers are rewarded with an excellent view of the San Joaquin Valley, the Merced River canyon, and the prominences of Yosemite's Half Dome, El Capitan, and Clouds Rest. Check with the Visitor Center in Mariposa for directions on reaching the trailhead.