The mill is located at the north end of the Knight's Ferry Covered Bridge. Built in 1860, it was first operated as a grist and flour mill; then at the turn of the century, it was redesigned to house generators and used its water power to produce electricity as one of California's first hydroelectric plants.

Underground pipes and shafts can be seen behind the stone house, which served as the miller's house and later as the office for the hyroelectric plant. The shafts channeled water from the dam upstream (ruins now) to the mill's waterwheel and later generators. The covered bridge was built in 1863, and at 330 feet, is the longest of its kind west of the Mississippi River. The town of Knight's Ferry dates from the California gold rush era and still has many of it's original buildings.