The 100-F Area is located in the northeastern portion of the 100-F/IU-2/IU-6 Area and covers approximately 4.63 km2 (1.79 mi2). It borders the 100-IU-2 OU to the west, the 100-F/IU-2/IU-6 Segment 4 Area to the south, and the Columbia River to the east. The 110-F Area includes several significant remaining structures including the 105-F Reactor, which is placed in an interim safe storage state and the 183-F Filter Plant Clear Well which now serves as a habitat for a large maternal colony of Yuma myotis bats.  The 100-F Area also includes an active borrow pit (100F Pit).

100-F Area History
The 100-F Area is the farthest downstream reactor area on the Hanford Site. Similar to other reactor areas, the focus of 100-F Area activities was the production of weapons grade plutonium. The 105-F Reactor was the third of the three original graphite moderated plutonium production reactors to operate at the Hanford Site. Construction of the 105-F Reactor began in 1943 and was completed in February 1945. The reactor and support facilities operated until 1965, when the reactor facility was deactivated and permanently retired from service. The 105-F Reactor was placed in interim safe storage (ISS) in 2003.

Many of the reactor support buildings were decommissioned along with the reactor in 1965.  Removal and demolition of support facilities was completed in 2012.

From 1945 through 1976, the 100-F Area contained an experimental animal farm that initially measured the effects of reactor effluents on fish. Later research included swine, sheep, dogs and rats.  The experimental animal farm facilities included numerous laboratories, barns, pens, pastures, kennels and waste facilities.  At one time, nearly 40 percent of the 100-F Area buildings were devoted to biological research. Facilities related to the experimental animal farm were decommissioned between 1978 and 1979.

The archaeological record of Native American occupation at the Hanford Site stretches back thousands of years. Typical Hanford archaeological sites include pit house villages, open campsites, fishing sites, hunting/kill sites, game drive complexes, quarries and spirit quest sites.

Activities within and immediately adjacent to the 100-F Area prior to the establishment of the Hanford Site also included gold mining along the Columbia River, homesteading, irrigated farm, livestock grazing, and steamboat and ferry transportation, as well as other activities.