Horn Pond is a 227-acre (92 ha) water body located on the border of Acton, Maine, and Wakefield, New Hampshire, in the United States.

Horn Pond's outlet is the Salmon Falls River which forms a natural border between Maine and New Hampshire and empties into the Piscataqua River east of Dover, New Hampshire, and ultimately the Gulf of Maine.

Horn Pond is classified as "Potentially Non-supporting" under the New Hampshire Department of Environmental Services' revised water quality standards for oligotrophic lakes.

[citation needed] Horn Pond water quality monitoring has been collected since 1982.

From this data, the median TP concentration is 8.0 parts per billion (ppb) and the mean transparency is 6.6 m (21.7 ft).