According to the United States Census Bureau, the township has a total area of 29.5 square miles (76.4 square kilometers), of which, 29.5 square miles (76.4 square kilometers) of it is land and 0.03% is water.
Millcreek Township is the second largest municipality in Erie County. Today land use in Millcreek is dedicated to retail, commercial and service-oriented businesses, to light industry, fine public and private schools, and residential areas. About 1% of the land is still zoned for agriculture.
Located within its borders is Edinboro University's Porreco Extension Center, Zuck Park, (donated for recreational use by the Zuck family), the Erie Golf Course, and the Asbury Woods Nature Center and Recreation Center, which was once the holdings and summer home of the Behrend family.