The Wisconsin primary results have all eyes on the Badger State on Tuesday night.
Mitt Romney was projected to finish in first in the Maryland primary and Washington, D.C. primary.
The former Massachusetts governor went into the contest leading rival candidates Rick Santorum, Newt Gingrich and Ron Paul, according to the latest polls.
HuffPost's Mark Blumenthal reports:
The Republican race enters April having just passed a significant milestone. As of the Louisiana primary on March 27, GOP presidential primaries or first-round caucuses have been held in 29 states and five territories, enough to account for just over half (52 percent) of the 2,286 delegates who will attend the Republican convention in Tampa, Fla., in August.
Click here for a rundown on who's ahead in the race.
Below, a live blog of the latest developments to unfold on primary day.