The history of Mack Trucks is intertwined with its Hagerstown, MD, assembly plant. First opened in 1961 as a 1 million sq. ft. facility on 280 acres, the plant now covers approximately 1.5 million sq. ft. and includes the company's Engine Development Lab along with production capabilities. Mack celebrated the facility's 50th birthday of powertrain assembly on May 4.

Originally built for $45 million, Mack has poured over $300 million into the facility since 2001 to modernize it, including the addition of robotics and the latest in automation.