Chapter 38 of Roughing It:

Loving and Carter identify Desert Wells as a station between Ragtown and Dayton. Pierson locates Desert Wells after Reed's Station, between Nevada and Dayton. Desert Wells existed sometime after July 1861, when it began to serve as a relay station for the Overland Mail Company line. During the last few months of its existence, the Pony Express also used the Desert Wells station facilities. (NPS)

Unionville is a small hamlet in Pershing County, Nevada, located south of I-80 and just west of State Route 400 on Unionville Road, with the most recent population estimate being approximately 20 people. The town's best years were during the 1870s, when it was an active mining and prospecting town serving the surrounding hilly region.

175.13–14  “Humboldt” was beginning to shriek for attention] This mining region was situated about a hundred seventy-five miles northeast of Carson City in the West Humboldt Mountains (see supplement B, map 2). Silver and gold were discovered in the area in 1860, and over the next year, Unionville, Humboldt City, and Star City—each in a separate mining district—emerged as the principal centers of mining activity.

About 11 A.M. we set off to cross the ten miles of valley that stretched between us and the summit of the western divide still separating us from Carson Lake. The land was a smooth saleratus plain, with curious masses of porous red and black basalt protruding from a ghastly white. The water-shed was apparently to the north, the benches were distinctly marked, and the bottom looked as if it were inundated every year.