The Pennsylvania primary on April 24 "could be a battle royal" for Republican presidential candidates, Fox 29 news reported.
With front runner Mitt Romney unable to solidify the nomination, the primary in Pennsylvania will likely be a hotly contested race between him and opponent Rick Santorum.
Santorum has the home-field advantage in the Keystone State. He served as Pennsylvania's senator from 1995 to 2007.
Candidates need 1,144 delegates for the nomination. As of today, Romney has 495 delegates, Santorum has 252 and Newt Gingrich has 131, according to the Wall Street Journal.
March 26 is the last day to register to vote in the primary election.