From the plaque:
Trading post, emigrant stop,
and mining camp of the 1850s, this became one of the remount
stations of the Central Overland Pony Express. On April
13, 1860, pony rider William (Sam) Hamilton changed horses
here at the Nevada House while carrying the first westbound
mail of the Pony Express from St. Joseph, Missouri to
Plaque placed by the California State Park Commission in cooperation with the James W. Marshall Chapter No.49, E. Clampus Vitus, Golden Chain Council of the Mother Lode, and the Central Overland Pony Express Trail Association. April 2, 1960.