Long-term data sets are important in the fields of ecology, hydrology, rangeland science, and geography. Remote sensing is an especially important component of such studies when spatial and temporal capabilities are important considerations. In many cases, satellite remote sensing is not adequate because of resolution or length of observation considerations. However, aerial photography, which extends back into the mid 1930s, is often overlooked. In order to find relevant imagery, considerable effort needs to be expended because the aerial photos over a particular study area can be scattered in a large number of archives across the country. Once the photos are assembled, digital scanning, proper documentation, storage, and a searchable data base are necessary to make easy and effective use of the aerial photos. The aerial photo data are of immense value to researchers, natural resource managers, students, and the general public.