The Coplay Cement Company Kilns are monuments to the Lehigh Valley’s role as the birthplace of the U.S. cement industry. Coplay Cement was founded by David O. Saylor, the man who first proved that modern, “portland” cement could be successfully manufactured in the United States instead of imported from Europe. The nine kilns, now standing in the middle of a community park, were once part of an entire complex of cement plants along the Lehigh River. Today, the kiln complex—an important symbol to the tiny borough of Coplay—is deteriorating dramatically. In particular, several large brick “blowouts” have prompted Lehigh County to fence the site off. This thesis examines the kilns’ history, from their invention in Denmark to the present day, and that history’s implication in the kilns’ present condition. The kilns have experienced dramatic changes in their use and environment since their first firing in 1895: originally enclosed within a four-story building, they were left exposed to the elements upon its demolition in 1950. In 1975, a greenhouse-like museum was constructed at the kilns’ base, which closed due to moisture issues in the 1990s. Through archival research, building archaeology, environmental monitoring, and thermal imaging, a comprehensive picture of the kilns’ deterioration patterns emerges. The results of the research highlight the special considerations involved in the conservation of industrial heritage sites—particularly of structural machines such as kilns.