In 1956, federal and regional transportation planners proposed an Inner Loop Expressway composed of three circumferential beltways for the District of Columbia.

The final design for the innermost loop made heavy use of cut-and-cover tunnels in order to minimize impacts to the city; one notable example that was built is the tunnel under the National Mall, between C Street SW and D Street NW, used by Interstate 395.

The innermost beltway would have formed a flattened oval centered on the Kennedy Center/Watergate complex in the west, running southeast along what is currently Ohio Drive SW until it linked with the Southwest Freeway portion of I-395, north along I-395 to L Street NW, and then west along a tunnel beneath K Street NW to join near the western nexus with the Whitehurst Freeway and Interstate 66—completing the loop.

[1] The middle beltway would have formed an arc along the northern portion of the city, running from the proposed Barney Circle Freeway (whose terminus would have been near Robert F. Kennedy Memorial Stadium) through Anacostia Park, cut northeast through the Trinidad neighborhood along Mt.

[1] D.C. residents strongly opposed both inner loops, upset that the freeways would have required the demolition of large numbers of houses and greatly affected city neighborhoods.