The Historic American Engineering Record (HAER) documentation of the Bronx River Parkway Reservation was developed in 2001-02 as a collaborative effort of the National Park Service and the Westchester County Department of Parks, Recreation and Conservation. In 1969, the National Park Service expanded its Depression-era Historic American Buildings Survey program to record America’s great engineering accomplishments and industrial sites. HAER documentation presents measured and interpretive drawings, large-format photographs and the written history of these sites to create a guide for their future use and development, as well as to create a permanent historical record in the event that the site is destroyed or altered. HAER documentation becomes part of the national collection at the Library of Congress with exact duplicates going to project co-sponsors -- in this case, the Westchester County Archives.