We especially thank those whose help made this compilation of information possible: Chester County GIS, George Fasic and the Chester County Planning Commission for census data; Rick Keen and Penn Pilot, and the Delaware Valley Regional Planning Commission for aerial photography; Andrew Homsey and Martha Corrozi Narvaez of the Water Resource Agency, University of Delaware for GIS data from the Delaware portion of the watershed; Anne Wolfe for GIS information from Delaware County, PA; Dorothy Merritts and Bob Walter at Franklin and Marshall College for access to historical data involving colonial mill ponds; Robert Lonsdorf at the Brandywine Conservancy for information on current dam locations; and students who performed GIS data entry and/or assisted in fieldwork (Andrew Brainard, Ashley Breslin, Abraham John, Laura Martin, Leslie Martin, Zach Nickens, Lori Timm, and David Yezuita).