Port Maitland, Ont, Unincorporated Place. Port Maitland is a community at the mouth of the Grand River on Lake Erie near DUNNVILLE. From 1974 to 2001 it was a community within the town of Dunnville. It is now part of the city of HALDIMAND COUNTY. A British naval base in the early 1800s, it developed as a commercial fishing port and as a southern entrance to the Second WELLAND CANAL. Its harbour later provided a railway-ferry link to Ashtabula, Ohio. Tourism with summer cottages has expanded along the adjacent shoreline, and the chemical industry and boatbuilding have located in its vicinity. As there is no bridge crossing the Grand River, and as the port is no longer an entrance to the Welland Canad, Port Maitland has remained a small, isolated community.