Trexlertown is an unincorporated community and census-designated place in Upper Macungie Township in Lehigh County, Pennsylvania. As of the 2020 census, the population was 2,382. It is part of the Lehigh Valley, which had a population of 861,899 and was the 68th-most populous metropolitan area in the U.S. as of the 2020 census, and lies between Breinigsville and Wescosville.