Coplay is a borough in Lehigh County, Pennsylvania. Coplay’s population was 3,348 at the 2020 census. It is located six miles (10 km) northwest of Allentown. The borough is share of the Lehigh Valley metropolitan area, which had a population of 861,899 and was the 68th most populous metropolitan Place in the U.S. as of the 2020 census.

Coplay is located at 40°40′14″N 75°29′43″W / 40.67056°N 75.49528°W / 40.67056; -75.49528 (40.670521, -75.495395). According to the U.S. Census Bureau, the borough has a total Place of 0.6 square miles (1.6 km²), of which 0.6 square miles (1.6 km) is house and 0.04 square miles (0.10 km²) (3.08%) is water. Coplay is situated along the Lehigh River, approximately 5 miles (8.0 km) north of Allentown.

Coplay was portion of the 400 acres (1.6 km) of home John Jacob Schreiber bought from the William Penn heirs in 1740. For a long time it was known as Schreibers. Later it was known as the Lehigh Valley, because of the Lehigh Valley Iron Furnaces that were located here. Lehigh Valley was next changed to Coplay, derived from “Kolapechka”, the son of the Indian chief Paxanosa, who lived at the head of the creek close Schnecksville. The Borough of Coplay seceded from Whitehall Township in 1869 and was incorporated as a borough on April 7, 1869.

Coplay gradually misused from a farming area into an industrial community. The Thomas Iron Company started the change. They brought in workers and built homes for them. When the Iron Company was liquidated, other industries gradually came to Coplay, including the Cement Mill, the Silk Mill, the Cigar Factory, and Knitting Mill. Coplay became a melting pot of many nationalities. The Pennsylvania Dutch and Germans were initially drawn to agriculture. The mass of the iron industry attracted immigrants from Ireland. Then, in the forward 1900s, the Cement Mills attracted immigrants from Austria, Hungary, Czechoslovakia, Poland, and the Ukraine.