Voters in three North Carolina Congressional districts head to the polls today to decide the GOP nominees in runoff elections. The Tar Heel State represents House Republicans’ most fertile territory this cycle, with the party expected to net a gain of at least two seats and as many as  four.

8th district

The most competitive race tonight is taking place in the 8th district, pitting former Hill aide Richard Hudson, backed by the establishment, against dentist Scott Keadle, a former Iredell County commissioner who is backed by the anti-tax Club for Growth.

“We’re finishing strong,” Hudson told Roll Call on Monday. “We knocked on 3,000 doors over the weekend. There’s a lot of momentum out there.”

Just how competitive is this race to take on deeply vulnerable Democratic Rep. Larry Kissell? Outside groups have spent more than $1.6 million on the primary and runoff, according to Federal Election Commission filings.

The Club for Growth and its affiliated groups have gone in heavy for Keadle, to the tune of more than $720,000. The YG Action Fund, a super PAC aligned with House Majority Leader Eric Cantor (Va.), has spent more than half a million dollars backing Hudson.

Hudson is a former district director for ex-Rep. Robin Hayes (R), whom Kissell unseated in 2008. Hayes is now the chairman of the state Republican Party.

Unaligned North Carolina GOP insiders see Hudson as the favorite to win, but with just a tiny fraction of the electorate expected to vote today, a surprise outcome is possible. Both candidates would have a better-than-even chance of unseating Kissell.

9th district

In the race to replace retiring Rep. Sue Myrick (R), former state Sen. Robert Pittenger faces Myrick-endorsed Mecklenburg County Commissioner Jim Pendergraph. Pittenger, who spent more than $940,000 from April 19 to June 27, has the edge over Pendergraph, who spent just $231,000 during the same period. The winner of the primary is almost certain to be the new Member from the Republican-leaning district.

11th district

In the western district of retiring Rep. Heath Shuler (D), real estate investor Mark Meadows has a strong edge over businessman Vance Patterson. In the May 8 eight-person primary, Meadows received 38 percent to Patterson’s 24 percent. GOP insiders believe Meadows has shored up his support and will win with ease.

The winner will face Democratic nominee Hayden Rogers, Shuler’s former chief of staff.

The GOP nominee is likely to win in a district that is expected to overwhelmingly favor Mitt Romney in November. Sen. John McCain (R-Ariz.) would have won the newly configured district in the 2008 presidential election with 58 percent of the vote.