[6][7] Wesner Springs at an elevation of 11,120 ft (3,390 m) on the slopes of Elk Mountain has a subarctic climate (Dfc), receiving 37 in (940 mm) of precipitation annually.

[8] San Miguel County was created in 1846 by the conquering United States' army in the Mexican-American War.

[9] In 1835, prior to the American conquest, the Mexican government had created grants of land in what became San Miguel County.

The grant lands quickly attracted settlers, mostly Hispanics, to the frontier of New Mexico in a region still menaced by Native American (Indian) raids.

The Santa Fe Trail, first travelled in 1821, passed through the county, linking New Mexico to the United States.

[11][12] The establishment of Fort Union nearby in 1851 increased the security of the region and provided employment for residents and a market for Las Vegas products.

[13] The coming of the railroad in 1879 expanded a market for ranch land and stimulated the livestock industry, especially of sheep for wool.

[14] By 1890, a few, mostly Anglo, ranchers controlled one-half of the grazing lands in San Miguel County.

[15] With Hispanic residents losing land and access to irrigation water to speculators, ranchers, and homesteaders, the secretive Gorras Blancas, "White Hats," burst on the scene in San Miguel County in 1889.

The Gorras Blancas were successful in gaining public support, eliminating many fences, and preserving access to common lands, but the movement faded in the early 1890s and the march toward converting common lands into private ownership soon resumed.

[16] By 2004, of the original land of the Las Vegas grant, only 10,340 acres (4,180 ha) remained in common ownership.

Donald Trump broke through this particular record in 2024, when he carried 35% of the vote; his performance in the county was the best by a Republican presidential candidate since Reagan in 1984.