The Wisconsin Historic Aerial Image Finder provides free online access to over 38,000 aerial photographs of Wisconsin from 1937-41. These photographs were originally acquired by the US Department of Agriculture. As part of a three-year project funded by the Ira and Ineva Reilly Baldwin Wisconsin Idea Endowment at the University of Wisconsin-Madison, these photographs were scanned, indexed, and made web-accessible through a map-based interface. The aerial photos are available for download by any user without fee or use restrictions.