Image courtesy of The Hamilton Co.

The Hamilton Co. plans to build a 72-unit apartment building next to a 181-unit apartment complex it recently bought in Woburn.

The firm acquired the 15 3-story buildings, plus a neighboring 3.2-acre development site for $59.5 million. The development parcel was already permitted for the apartments.

Handling the transaction for Hamilton were David Ross of Hunneman, the company said in a statement. CBRE’s Simon Butler and Biria St. John were the listing brokers.

Mill Street Garden Apartments is Boston-based Hamilton’s third acquisition in Woburn. Hamilton purchased the 220-unit Westgate Apartments in 1977 and the 44-unit Brookside Apartments in 2000. Hamilton also owns apartment complexes in nearby Winchester, Lexington and Arlington