In 1906, Harry Clay Trexler started purchasing farms in Lowhill and North Whitehall townships to create a preserve to help protect bison, elk, and white-tailed deer. He purchased a total of 36 farms comprising 1,108 acres (448 ha) before he died, and then bequeathed the land to Lehigh County. In 1935, the area officially became the Trexler-Lehigh County Game Preserve.[4]
Construction on the children's zoo in the park began in 1974. When it opened, the zoo included petting and feeding exhibits and exotic animals from Africa, Asia, and Australia.[5]
In 2004, with the original purpose of saving native species accomplished, the county opened the entire preserve to the public.[4] At the same time, the Lehigh Valley Zoological Society took over management of the zoo within the park.[5]