Ontario North was a federal electoral district represented in the House of Commons of Canada from 1867 to 1925.

The North Riding of Ontario initially consisted of the Townships of Reach, Uxbridge, Brock, Scott, Thorah, Mara, Rama and Scugog.

In 1882, it was redefined to exclude the townships of Reach and Uxbridge, and to include the townships of Morrison, Ryde, Draper, Oakley, Macaulay, Maclean and Ridout and the villages of Bracebridge and Cannington.

In 1892, "North Ontario" was defined to exclude the township of Scugog, and to include the village of Beaverton.

In 1903, it was redefined to consist of the townships of Brock, Mara, Rama, Scott, Thora and Uxbridge, the town of Uxbridge, and the villages of Beaverton and Cannington.