Sewell, Jonathan, 1766–1839, Canadian jurist, b. Cambridge, Mass. He was educated in England and emigrated to Canada in 1785. A lawyer, he became attorney general of Lower Canada (Quebec) in 1795 and sat in the Legislative Assembly (1796–1808). While chief justice (1808–38) of Lower Canada, he made a decision (1818) that was the basis for drawing the boundary between Upper Canada (Ontario) and Lower Canada. President (1808–29) of the executive council and speaker (1809–39) of the legislative council, he was one of the earliest advocates of confederation.