The Pelton Water Wheel, first commercially manufactured here at George Allan's Foundry and Machine Works in 1879, was a major advancement in water power utilization and greatly advanced hard-rock mining. Its unique feature was a series of paired buckets, shaped like bowls of spoons and separated by a splitter, that divided the incoming water jets into two parts. By the late 1800s, the Pelton Wheels were providing energy to operate industrial machinery throughout the world. In 1888, Lester Pelton moved his business to San Francisco, but granted continuing manufacturing rights to Allan's Foundry, where the wheels were manufactured into the early 1900s, when most local mines shifted to electric power.

California Registered Historical Landmark No. 1012

Plaque placed by the State Department of Parks and Recreation in cooperation with the Nevada County Cultural Preservation Trust and Pacific Gas & Electric Co., May 11, 1994.