Prince William County Republican Supervisor John T. Stirrup plans to make a run for the new Virginia Senate seat in Northern Virginia, he said on his Web site Monday.

Stirrup, who has spent the last eight years representing the Gainesville district on the Board of County Supervisors, will vie for the 13th district Senate seat, which was created during the state’s redistricting process. The district straddles Prince William and Loudoun counties.

“It was a great opportunity because an open seat doesn’t come along very often,” Stirrup said, noting he will not seek re-election to the county board. “It is a great opportunity for me to bring my solution-based conservatism to Richmond.”

Former Loudoun County delegate Dick Black ( R ), perhaps best known for distributing plastic models of fetuses to fellow lawmakers preparing to vote on abortion issues, said he plans to run for seat, along with Prince William resident Bob FitzSimmonds (R) who made an unsuccessful run for the senate in 2007.

Stirrup, 54, has fought for lower taxes, tougher immigration laws and responsible growth while serving on the board. He helped spearhead the effort to get a new immigration policy passed in the county and also was one of two supervisors to vote against the county’s fiscal 2012 budget because it will raise taxes slightly.

A native of New Jersey, Stirrup moved to Northern Virginia in 1982, spending the last 13 years in Prince William with his wife and daughter. Stirrup has worked with a wide range of state and federal officials during his career. He served as a political appointee for seven years during the Reagan Administration and also as chief of staff for a member of Congress.

Stirrup has served as a government affairs executive for a transportation association and has also worked for the “big five” accounting firms, according to his Web site.

The race for the 13th district Senate seat could prove to be one of the state’s most interesting. Democrats are trying to hold their razor thin 22 to 18 majority in the chamber. They could look to the new seat, created by merging Republican Fred Quayle’s and Republican Harry Blevin’s seats in Hampton roads, as a place to possibly pick up ground in the Senate by snatching a seat from Republicans.

Black is hoping to win the seat in order to make a comeback. The deeply conservative Republican was defeated in 2005 after serving seven years in the General Assembly.

“This district could ultimately decide who controls the majority in the Senate,” Stirrup said. “It’s imperative we don’t nominate a candidate who can’t win in November. I know the other candidates well…but their track records speak for themselves in their electability over mine.”