Site information:

On lawn at entrance station, Castle Crags State Park, 0.3 mi W of I-5, Castella

The plaque is located in the State Park, which generally requires a fee, but when I visited the ranger was kind enough to let me photograph the plaque for free.

I have been unable to pinpoint which rock is the specific "Battle Rock" mentioned, but the site is more about commemorating the battle itself.

41.148220,-122.321456

Plaque information:

State plaque

Plaque text:

Battle Rock

Battle of the Crags was fought below Battle Rock in June 1855. This conflict between the Modoc Indians and the settlers resulted from miners destroying the native fishing waters in the Lower Soda Springs area. Settlers led by Squire Reuben Gibson and Mountain Joe Doblondy, with local Indians led by their Chief Weilputus, engaged Modocs, killed their Chief Dorcas Della, and dispersed them. Poet Joaquin Miller and other settlers were wounded.

Plaque placed by the State Deptartment of Parks and Recreation in cooperation with the ancient and honorable order of E Clampus Vitus, Trinitarianus Chapter #62, July 26, 1984.

Registered 3/29/1933