The Old Post Office Building is a historic building in Lynn, Massachusetts. The two-story Colonial Revival building was built in 1897 to serve as the growing city's new post office. It is one of the city's best examples of Colonial Revival styling, and features distinctive copper sheathed domes. The building was expanded c. 1912 with a wing in the back, and replaced by the present post office in 1933. It has since been used principally as an office building.