[2] It was named after Nathaniel Lyon, the first Union General to be killed in the Civil War.

[3] Its first county seat was established at Dayton on November 29, 1861,[4] which had just changed its name from Nevada City in 1862, and which had been called Chinatown before that.

There were stories that it was named for Captain Robert Lyon, a survivor of the Pyramid Lake War in 1860, but Nevada State Archives staff discovered a county seal with the picture of the Civil War general, settling the conflict.

The highest point is approximately 10,565 feet (3,220 m) on the northeast ridge of Middle Sister, the peak of which is located in adjacent Mono County, California, while the highest independent mountain completely within Lyon County is the nearby East Sister.

[14] As of the 2010 United States Census, there were 51,980 people, 19,808 households, and 14,137 families living in the county.

An advisory question about Lyon County's legal brothels was put on the 2018 ballot.

While the line west of Silver Springs was removed, the line from Hazen to Walker Lake (now standard gauge) is still in place, and used several times each week by the Union Pacific to service the NV Energy Fort Churchill Generating Station, near Yerington.

The Eagle Salt Works Railroad ran for 13.5 miles, primarily on the original Central Pacific grade from Luva (two miles east of Fernley) to Eagle Salt Works Railroad.

The Nevada Copper Belt Railroad ran on the west side of the Mason Valley.

Amtrak's California Zephyr passenger train passes through, but does not stop in Lyon County.

The California Zephyr runs from the San Francisco Bay Area to Chicago via Salt Lake City, Denver and Omaha.

There are several open ranches, including: All are located in Mound House, which is on US Highway 50 adjacent to the line dividing Lyon and Carson City counties.

Several gambling casinos are located in various parts of Lyon County, as are numerous restaurants, clubs, saloons, etc.