Russell County is known as a historic county in the Canadian province of Ontario.
It was created in 1800 from a portion of Stormont County. In 1820, the county was united with Prescott County to form United Counties of Prescott and Russell which is still an upper-tier municipality
The county's Cumberland Township became part of the Regional Municipality of Ottawa–Carleton in 1969, and is now part of the single-tier city of Ottawa.