Location of Cement Plants and Routes used to Philadelphia

The heart of America’s cement industry on the eve of entry into World War I.

This unusual map captures one of America’s most productive cement-producing districts during the early 20th century. Though the broader image is bounded approximately by the Hudson, Susquehanna, and Delaware Rivers, industrial activity is heavily concentrated within Pennsylvania’s Lehigh Valley between Allentown and Slatington.

The robust network of railroad lines connecting individual cement mills to major urban centers and tidewater ports is strongly emphasized, with a key in the lower left outlining the routes of seven distinct rail operators.

Issued at a scale of 1 in. = 6 miles, this blueprint-style map was created anonymously and is dated September 15, 1916 (though the paper stock suggests this example may be a somewhat later reprint). At the time of compilation, the United States was undergoing a massive national defense preparedness drive in response to World War I in Europe. Portland cement was a vital strategic material required for military mobilization; essential for expanding dry docks, naval port facilities, industrial factories, and heavy coastal defense fortifications.