The Seigneury of L'Orignal
This area, the present township of Longueuil, was granted in 1674 to François Prevost, Town Mayor of Quebec, and was the first seigneury in what is now Ontario. Known originally as the seigneury of "Pointe a L'Orignac", it was not developed until the Hon. Joseph Le Moyne de Longueuil, seigneur since 1778, granted portions to settlers during 1784-90. Nathaniel Hazard Treadwell purchased the seigneury in 1796, built mills and roads and expanded settlement. A United States citizen, Treadwell left Canada during the War of 1812 and forfeited his lands, but later regained these and sold the seigneury to his own son Charles in 1824. By 1873 most of the seigneurial lands had passed out of the family.
Plaque via Alan L. Brown's site Ontario Plaques. Full page here.