Geophysical measurements were conducted to locate building sites at a nineteenth-century fort in Michigan. The survey area, Fort Wilkins, was built during the copper boom of the 1840s and is located at the tip of the Keweenaw Peninsula in the Upper Peninsula of Michigan. Resistivity and magnetic surveys were conducted over the locations of former privies, a guard house, a carpenter house, and a blacksmith shop. The resistivity surveys were made using a half-Schlumberger array with electrode spacings of 0.3, 0.6, 1.0, 1.5, and 2.0 m. A masonry foundation and the privies are indicated by high-low resistivity pairs. Analog modeling was used to create anomalies similar to those seen over the privies. Measurements of the vertical magnetic gradient yielded anomalies which are associated primarily with modern objects.