The truckmaker owns 281 acres. The area to be sold is adjacent to Interstate 81, General Manager Ross Rhoads said.
Access to an industrial park would be through the Maugans Avenue entrance to the Mack campus, Rhoads said. A 2,400-foot road spur would split off the entrance road parallel to I-81, connecting to five industrial lots of varying sizes.
Rhoads said the company would market the lots after it receives the necessary approvals. He said he didn't know what types of companies might move in, or how many jobs they would provide.
Rhoads said the lots probably would be sold through a broker.
The site has rail access that Mack has never used, Rhoads said. Other utilities, including water and sewer, are available.
Mack, once Washington County's largest private employer, originally bought the 281 acres in order to have room to expand the factory to twice its current size, officials said. But employment at the factory has dropped to about 1,200 employees, down from a high of about 4,500 employees in the late 1970s.
"It's obvious today that growth is not going to take place," Rhoads said.
About a year ago, the company started seeking options for use of the vacant land on its property, Rhoads said.
The company also plans to develop an additional 8.6-acre site at its entrance on U.S. 11 near Dentler Bros. Furniture. The company has asked that its land there be rezoned from Industrial General to Business General, which would allow a variety of commercial uses.
Access to the lots would be provided by the existing Mack entrance road.
Mack officials said the industrial designation was not appropriate to land fronting U.S. 11, which is marked by strip commercial development.
The Washington County Commissioners have not yet voted on the rezoning request. Comments can be submitted for the record for 10 days.
Mack, headquartered in Allentown, Pa., makes powertrains in Hagerstown.