The main building of Seaman’s Retreat, the third building constructed for the newly founded hospital, dates from 1834-1853. An imposing granite ashlar structure, built by Abraham P. Maybie, the main building displays Greek Revival elements while evoking characteristics of the earlier Georgian tradition. Early 20th-century alterations retain and elaborate the Greek Revival character of the original building which continues to evoke the important role it has played in medical research and in providing healthcare to thousands of seamen.