Fort Crook, Military fort at Fall River Mills, United States.

Fort Crook was a military installation near Fall River Mills consisting of about 25 log buildings surrounded by a tall stockade of pine poles. The layout followed standard frontier fort design to provide shelter and security for the troops and nearby travelers.

Founded in 1857 as Camp Hollenbush, the installation guarded major travel routes and ferry crossings in the region. Military operations there continued until 1869, when the troops were withdrawn and the outpost was abandoned.

The fort's name honours two men: Assistant Surgeon Calvin G. Hollenbush, after whom the original Camp Hollenbush was named, and 1st Lieutenant George Crook of the 4th U.S. Infantry, wounded by an Indian arrow during the 1857 Pitt River Expedition. The Fort Crook Historical Society, which placed the site's marker on 11 November 1934, keeps this record, and the Fort Crook Museum in Fall River Mills holds a restored cabin from the fort site.

The original fort site northeast of Fall River Mills has no remains; the marker and museum lie in Fall River Mills at the east intersection of McArthur Road and Soldier Mountain Road. A restored cabin from the fort and the 2009 round barn stand on the museum grounds. The Fort Crook Historical Society placed the marker on November 11, 1934.

A round barn reconstructed in 2009 marks where soldiers trained wild horses for Army use. This detail reveals a lesser-known function of the fort beyond protecting travelers passing through the region.