John Armstrong had been elected for this seat (term 1803–1809) in February 1804, after the resignation of Theodorus Bailey.
Armstrong took his seat on February 25, but resigned on June 30, 1804, after his appointment as U.S. Minister to France.
Congressman Dr. Samuel L. Mitchill was the candidate of the Democratic-Republican Party.
Senator Rufus King was the candidate of the Federalist Party.
Mitchill took his seat on November 23, 1804, and served until the end of the term on March 3, 1809.