This is one of the oldest functioning post offices in the United States. It’s in the tiny town of Three Rivers, just outside the south entrance to Sequoia National Park.

Built from local cedar and redwood in 1910, the building measures just 12 feet by 15 feet. It has remained in almost continuous operation since then—though as of 2010, it is no longer a full-service post office. Today the office is manned by volunteers and serves about 50 people who hold mailboxes in the little outpost.

There is also a monument to the Kaweah Colony at the front, commemorating the Kaweah Cooperative Colony, a small settlement that made the first roads into what is now Sequoia National Park.