Thunderbird Archaeology (Wetland Studies and Solutions)
R. Christopher Goodwin & Associates (Frederick, MD)
John Milner Associates (Now Commonwealth Heritage Group, Alexandria, VA)
EHT Traceries (Washington, DC)
DC Preservation League’s Contractor Database
For-Profit Historical Research Companies (Not endorsed by the program, but for reference)
History Associates, Inc.
Historical Research Associates, Inc.
History Works, Inc.,
NARA (National Archives) Listing
LOC (Library of Congress) PDF Listing
Professional Organizations and Resources