The North Sydenham River is a river in the municipalities of Saint Clair (Lambton County) and Chatham-Kent (formerly in Kent County) in Southwestern Ontario, Canada.

[1][2][4][5][6] It is a tributary of the Sydenham River, and is part of the Great Lakes Basin.

It flows first southwest, then southeast, then heads south.

The river enters Chatham-Kent, takes in the right tributary Running Creek, and reaches its mouth at the Sydenham River, at an elevation of 175 metres (574 ft), at the community of Wallaceburg.

[3] The Sydenham River flows via the Chenail Ecarté (The Snye), Lake St. Clair and the Detroit River to Lake Erie.