A special election was held in Delaware's at-large congressional district on October 6, 1807 to fill a vacancy left by the resignation of James M. Broom (F)
Background
In 1806, James M. Broom (F) was re-elected to a second term in Delaware's at-large district. He'd won his first term in a special election caused by James A. Bayard's election to the Senate. However, Broom did not serve this second term, instead resigning as well, before the start of the Tenth Congress. A special election was held for his replacement.
References
Delaware's at-large congressional district special election, 1807 Wikipedia(Text) CC BY-SA