The Weston Observatory is a historic folly on Oak Hill, the high point of Derryfield Park in Manchester, New Hampshire.

Built in 1897, the granite tower is a prominent local landmark, given to the city by James A. Weston, a Manchester native who served twice as governor of New Hampshire.

[1] The Weston Observatory is located near the center of Derryfield Park, at the summit of Oak Hill, a prominence that affords fine views of the city to the west.

Its base consists of several large pieces of cut granite, with the entrance at the west side, surmounted by a lintel engraved with Weston's name.

It was originally open to the public during the warmer months of the year, but was commandeered for military use during the Second World War, and was thereafter used to house police transmitters.