One of the most closely watched U.S. House races in the country is in western Pennsylvania, where Democratic incumbent Mark Critz is facing a stiff challenge from Republican attorney Keith Rothfus.

  

A GOP victory could help solidify the party's control in the House.

  

The race has been flooded with $9.9 million in spending by outside groups, more than any other House race in the nation.

  

Critz has been fighting to keep his seat since winning the special election in 2010 after his former boss, longtime Democratic congressman John Murtha, died in office.

  

The latest challenge comes from the GOP's Rothfus in a newly-drawn 12th Congressional District that tends to vote Republican despite a slim majority of registered Democrats.

  

There were no early surprises in other Pennsylvania congressional races.