Mitt Romney in Fairfax County on Wednesday

GOP presidential candidate Mitt Romney will join Virginia Gov. Bob McDonnell on a swing through northern Virginia Wednesday.

Romney and McDonnell will stop at Fairfax County Republican headquarters Wednesday morning to thank volunteers for their efforts ahead of next month's legislative elections in Virginia.

Republicans are hoping to gain control of the state Senate; they already control of the House of Delegates and governor's mansion.

McDonnell, a possible vice presidential contender, has not made an endorsement in the presidential race.

Both Romney and McDonnell are also doing some fundraising while they're in the wealthy northern Virginia suburbs. Romney attended a fundraiser thrown on his behalf Tuesday night by supporter Bobbie Kilberg in McLean. McDonnell attended several fundraisers for GOP General Assembly candidates Tuesday, with more scheduled on Wednesday.