This fascinating museum at the edge of town, overlooking the river, was built in 1807 to resemble a Scottish manor house. It was then radically added onto and altered by a local cotton trader (yes, a cotton trader) named Richard Tucker who in 1858 transformed the house, adding a rather showy piazza and other additions. Thanks to a reversal of fortune, the house wasn’t renovated again—to the benefit of modern visitors, who can see what life was like for high society in Maine in the mid-19th century. Tucker’s daughter eventually donated the home to New England’s antiquities society, which maintains it today; Castle staff give tours of the manse, which features a wonderful, long staircase and trompe-l’oeil-style plaster that looks remarkably like solid wood. Find it overlooking the river (behind Sarah’s Café).