Aerial maps of Delaware, spanning from 1937 to the present, are available in an online digital archives maintained by the Delaware Environmental Monitoring and Analysis Center. Initially captured during flights flown over the region, the photography shows what the region looked like at various points. Typically termed orthophotography once the data has been geocorrected, the pictures were used in local map making.
This virtual service is helpful to local history researchers and genealogists. It allows investigators to easily acquire detailed visual representations showing the nature of development of parcels for a period of over a century, which is a valuable tool for finding old homes, cemeteries, roads, streams and much more. It is also a strong source for studying the evolution of communities and rural areas throughout the 20th century.
Simply by clicking the mouse on the desired sector of the map, the virtual visitor has access to aerial images. They show how the land appeared in 1937, 1954, 1961, 1968, 1992, 1997, 2002, 2007, and 2010
Here is the link to the homepage with instructions.