It has been represented by Democrat Barbara Favola since 2012, succeeding retiring fellow Democrat Mary Margaret Whipple.

District 31 stretches along the Potomac River in parts of Arlington, Fairfax, and Loudoun counties, including some or all of McLean, Langley, Great Falls, and Lowes Island.

The sections of Arlington covered include the neighborhoods of Arlington Forest, Arlington View, Ballston, Cherrydale, Clarendon, Courthouse, Glen Carlyn, Lyon Village, Rosslyn, Virginia Square and Westover.

[4] It lies directly across the river from Maryland and the District of Columbia.

[1] All election results below took place prior to 2011 redistricting, and thus were under different district lines.