Rep. Tim Bishop (D) has defeated Republican challenger Randy Altschuler in New York’s 1st district, a victory finalized by an Altschuler concession Wednesday morning in the nation’s final outstanding House race that cements GOP gains in the 2010 House midterms at 63 seats.

It was a roller-coaster ballot-counting process that saw several lead changes and court hearings over the past 36 days, but Bishop’s ultimate margin of victory was 263 votes out of more than 194,000 cast in the Long Island district.

In his concession statement, Altschuler notes that his campaign “has uncovered numerous instances of absentee ballots that may have been unlawfully cast” but will not pursue further legal action in part because “their number is too small to alter the outcome of the election.”

“After consulting with my family and campaign staff, I am ending my campaign and offering congratulations to Congressman Tim Bishop on his victory,” Altschuler said.

“Although Newsday, The New York Times and the Bishop campaign have all called for a hand recount of all the ballots cast on Election Day, I will not support such an action as I feel its cost will place an unnecessary burden on the taxpayers of Suffolk County.”

“I plan to stay active in politics and continue to speak out on the issues that affect the residents of Suffolk County, our state and our nation,” he continued.

“I intend to play an active role in building the Republican and Conservative Party voices in both Suffolk County and New York State.”