Fairfax County Supervisor Linda Q. Smyth announced Tuesday that she will not seek reelection next fall, after a 15-year career in which she played an instrumental role in the redevelopment of Tysons Corner.

“It’s truly been a pleasure to work with all of you, but this will be my last term in office,” Smyth (D-Providence) told her fellow board members during a portion of the meeting allotted to issues that are not on the agenda.

“I suspect this will be a busy year in Providence,” she said. “We may have a lot of land use [cases] to finish up. So, I am apologizing in advance for all the work that may need to get done next year.”

The retirement of Smyth, 69, is part of a political transformation occurring in Virginia’s largest jurisdiction, with several longtime elected leaders either stepping down or considering it or facing vigorous challengers.

Supervisor John C. Cook (R-Braddock) announced last month that he won’t run for office next November. Board Chairman Sharon Bulova (D-At Large) and Supervisor Catherine M. Hudgins (D-Hunter Mill) are mulling whether to seek new terms.

Besides Tysons, Smyth’s district includes the Mosaic retail complex in Merrifield and the increasingly Latino immigrant neighborhoods just outside Falls Church.

On Tuesday, school board member Dalia Palchik announced she will run for Smyth’s seat as a Democrat. Erika Milena Yalowitz, 39, a Democrat who is vice president of the Providence District Council of homeowner groups, has already announced her candidacy.

“I’d like to thank Linda Smyth for her tireless efforts on behalf of Providence District,” Palchik said in a statement. “I’m running for Providence District Supervisor and I will formally announce it next week.”