The Columbia Commonwealth was one of the thirteen commonwealths of the pre-War United States of America. Created in the early 21st century, it was comprised of the former states of Maryland and Virginia, as well as the District of Columbia.
Capital Wasteland
The Capital Wasteland spans much of the District of Columbia, as well as portions of both Maryland to the north and Virginia to the south. It is having power struggles between Brotherhood of the area, the Enclave survivors, and the super mutants. Vice and crime is rampant in the area, with raiders, mercenary bands, and creatures pillaging any and all things that move.
Point Lookout
Another portion of Maryland, this time south of the Capital Wasteland proper, is available in the DLC content Point Lookout. Swamplands and swampfolk abominations are abundant, and while certain areas weren't directly hit by the bombs, the land and inhabitants are still being affected by radiation and disease, carried downstream from irradiated areas.
Known locations
Appearances
Parts of the Columbia Commonwealth, most notably around the Potomac river, appear in Fallout 3.