Potomac primary

The results on both sides were fairly unsurprising according to opinion polling, with both John McCain and Barack Obama winning by substantial margins.

For Obama, however, the race had been significant as a major source of delegates in the close Democratic race, with him garnering a net gain of 50 delegates.

President Barack Obama ran unopposed.

In the 2016 election, on both the Republican and Democratic sides, Maryland, Virginia and the District of Columbia held their primaries on three separate days.

Virginia's 2016 primaries were part of Super Tuesday, while Maryland's took place on April 26.

Two states and one district held caucuses or primary elections in the Potomac primary, 2008. Purple represents contests for both parties (3).