James Irwin Hartt

James Irwin Hartt (March 2, 1866 – February 17, 1935) was an Irish-born lumberman and political figure in Ontario. He represented Simcoe East in the Legislative Assembly of Ontario from 1911 to 1919 as a Conservative member.

The son of Isaac B. Hartt and Jane Irwin, he came to Canada in 1884. In 1897, Hartt married Flora Carter. He ran unsuccessfully for a seat in the Ontario assembly in 1908. Hartt served on the municipal council for Orillia. He died at Orillia in 1935.