The Castine Post Office is the second oldest U.S. post office continuously operating in the same building.
The building began its life in 1814 as the home of the Hancock County Registry of Deeds and an office for the short-lived Castine Bank. In 1833 the federal government purchased the bank’s share of the building, to use as a post office and to serve the growing needs of the Penobscot District Custom House. Castine was one of ten Maine ports designated in 1789 to conduct the maritime trade business of the United States Treasury Department. The Custom House was closed in 1919 and the post office took over the entire building.
From 1869 to 1870, the building was remodeled in an ornate Victorian style. In 1880 the building was further decorated with wooden panels painted black and designs incised in gold. The decorations included portraits of George Washington, Abraham Lincoln, Ulysses S. Grant, and the Baron de Saint-Castin. Those were painted over by 1896.
In the 1960s the United States Post Office Department wanted to move to a more cost-efficient space, but Castine citizens rallied to preserve the unique building and its continued use as their post office.