You’re forgiven if you don’t realize there’s an election in Alexandria , Arlington and parts of Fairfax on Thursday.

Thanks to last week’s decision by Gov. Bob McDonnell (R) to set a special election Sept. 4 to fill two General Assembly seats, Democrats have organized a caucus and Republicans will have a canvas Thursday to choose a candidate for the 45th District seat, soon to be vacated by Del. David Englin (D).

Del. David Englin ( D-Arlington) (Steve Helber/AP)

The district covers the east side of Alexandria, parts of southern Arlington and a part of the Belle Haven area of Fairfax County. To cast a vote for one of the two candidates in the Democratic caucus, turn up Thursday from 5 to 9 p.m. at Lyles Crouch Traditional Academy, 530 South St. Asaph St. in Alexandria or Saturday from 10 a.m. to 5 p.m. at the Cora Kelly Recreation Center, 25 W. Reed Ave., Alexandria.

Democrats Karen Gautney and Rob Krupicka are both running for the nomination. Gautney has been endorsed by the incumbent (until Aug. 31) Englin, and Krupicka was endorsed this morning by State Sen. Adam Ebbin (D). Ebbin defeated Krupicka in the Democratic primary for that seat by 331 votes almost a year ago, on the day of the August earthquake.

Republicans have yet to announce a candidate; those interested must file by 5 p.m. today. If more than one person is interested, the party will hold a canvas Thursday from 7 to 9 p.m. at the Minnie Howard campus of T.C. Williams High School, 3801 W. Braddock Rd. in Alexandria; Springfield Victory Center, 6320 Augusta Dr., Springfield; and Arlington County Republican headquarters, 405 S. Glebe Rd., Arlington.

The local Democrats are not thrilled by the pop-up nature of the election. Alexandria Democratic Committee chair Dak Hardwick last week noted that it’s the first Tuesday after Labor Day, the first day of school and will cost local governments “tens of thousands of dollars” to have the vote in September rather than on the general election day two months later.

The governor’s spokesman said McDonnell felt it was important to move quickly, particularly since the outcome could result in another vacancy in the General Assembly. Del. Kenneth Cooper Alexander (D-Norfolk) announced this week that he will seek the late Sen. Yvonne Miller’s seat. Miller (D-Norfolk) died last month. Should he win, another special election will be needed to fill his House seat.