Kady Finley, 26, a paralegal, has filed to run for Denton City Council District 2.
Council member Keely Briggs resigned the seat effective in May to run for mayor against District 1 council member Gerard Hudspeth, who did the same.
Finley faces Daniel Clanton, 49, a delivery manager, in the race to fill the unexpired term. She appointed William Michael Hensley as her campaign treasurer.
Friday is the last day for candidates to file for mayor and the two at-large seats on the City Council, Place 5 and 6.
The deadline for candidates to file for District 1 and 2 is Tuesday, March 3.