Jeff Frederick, the ousted leader of the Republican Party of Virginia , will officially kick off his campaign for state Senate on Saturday in Dumfries.

Frederick will be at his campaign headquarters, located at 17934 Main St. in Dumfries, from 10 a.m. to 11 a.m. on Saturday. The office, which Frederick officials said has been open for about a month now, is located across from the Dumfries Post Office and adjacent to Majestic Glass & Mirror.

The former state delegate filed paperwork in June for the 36th District Senate seat, which spans Prince William, Stafford and Fairfax counties. Frederick will face Tito “the builder” Muñoz in the Aug. 23 Republican primary. The two are trying to oust Democratic Sen. Linda “Toddy” Puller, who has held the seat since 1999.

“I think I should be able to win and continue to serve the people well,” Puller said, noting she doesn’t know Muñoz but worked with Frederick until he left the House in January 2010.

Frederick said he wants to get back to Richmond to promote job creation and “common sense” solutions to transportation problems that plague the region.

Muñoz, who owns a construction company in Woodbridge and is a conservative Latino voice on local radio, said he will focus on job creation, tax cuts for businesses and energy independence. Muñoz kicked off his campaign in June with former governor and U.S. senator George Allen, who endorsed Muñoz for the seat. Allen is seeking the Republican nomination for U.S. Senate in 2012.

Coming Thursday in The Post: Marc Fisher reports on the faceoff between Muñoz and Frederick, a race that reflects the Republicans’ nationwide struggle over how ideologically pure candidates must be to win the enthusiasm of Tea Party conservatives, yet still be electable in November.