Shows outline of counties under the jurisdiction of the Southwestern Pennsylvania Heritage Preservation Commission. Relief shown by shading. Includes text of "Commission mission statement" and ill. Available also through the Library of Congress Web site as a raster image. ARP
United States. Department Of The Interior. Southwestern Pennsylvania Heritage Preservation Commission
<a rel="nofollow" class="external free" href="https://www.loc.gov/item/92686679/">https://www.loc.gov/item/92686679/</a>