From the plaque:
From 1853 until 1870, Keysville
was a center of both placer and quartz gold mining. On
the knoll just below the townsite may still be seen the
outlines of an earthworks fort, built to meet a possible
Indian attack in 1863. The original Keyes mine is still active.
Dedicated April 25, 1937. Bakersfield Parlor No 42 N.S.G.W., El Tejon Parlor No 239 N.D.G.W., Kern County Chamber of Commerce. Department of Natural Resources.