Pleasant Valley is an unincorporated community located within Hopewell Township in Mercer County, in the U.S. state of New Jersey.

[2] The community is located along the northern edge of a 30,000-acre (12,000 ha) plot bought by the governor of West Jersey, Daniel Coxe, in 1685.

[3][4] The Pleasant Valley Historic District is a 1,565-acre (633 ha) historic district located along Pleasant Valley Road, Valley Road, Woodens Lane and Hunter Road in the community, and extending into West Amwell Township in Hunterdon County.

The district was added to the National Register of Historic Places on June 14, 1991, for its significance in agriculture, architecture, and exploration/settlement.

The individually listed Howell Living History Farm is central to the district.