Henry A. "Hock" Mason arrived in 1859, becoming the first settler in the valley which would later bear his name. In 1870, William Lee homesteaded 160 acres in the valley (at the location which would evolve into Yerington) and built a two-story boarding house to serve travelers, as several roads passed through the area. Lee convinced men from Pine Grove to come and open new businesses on his homestead, and soon a community nicknamed "Pizen Switch" (due to poor quality whiskey served at Jim Downey's saloon, which they called 'poison' or 'pizen') or just "The Switch" came into being. The next year, the Mason Valley post office was opened to serve the area.

In the 1870s, the thriving town began seeking a name to differentiate it from the surrounding valley. Greenfield was the name chosen, and the town was officially re-christened in 1879. Soon attempts were made to rename the post office to reflect the change, but the application was denied due to there being too many towns called Greenfield in the country. By 1894, the name Yerington was chosen to honor Henry M. Yerington, president of the Carson & Colorado Railroad, with the hopes that he would build a spur line to town from Wabuska. The spur would never materialize, but nevertheless the town became known as Yerington; a place name that to this day is unique in the world.

Through the twentieth century and into the twenty-first, Yerington has remained a modest but important agricultural center. It became the Lyon County seat in 1911 after fire destroyed the courthouse in Dayton, and has grown to a population of just over 3000. It is also a significant producer of onions and garlic, and being home to some of the country's largest onion producers has earned the nickname "The Onion Capital of the West".

Mason Valley
YeringtonSage Crest Drive-In
MasonBluestone MineNordyke