Whitlocks Mill Light stands on the south bank of the St. Croix River in Calais, Maine, at a bend in the river. Established in 1892, it began with a lantern hung in a tree by the local miller. The present station dates from 1910, when the brick tower and support buildings were built and a fourth-order Fresnel lens installed. Notable as Maine’s northernmost lighthouse and the last built in the state, it includes a distinctive pyramidal bell house and a typical brick oil house. Automated in 1969, the station later passed through public and private stewardship while remaining an important part of the river’s navigation history.