Portsmouth Harbor Lighthouse was built in 1771 and is the tenth of eleven light stations built before the American Revolution. In 1771, Royal Governor John Wentworth had a hexagonal wooden lighthouse built at Fort Point. The lighthouse was a shingled wooden structure with a copper roof and an iron lantern. It was lit by three copper oil lamps.
The original tower was replaced in 1804 by an 80-foot octagonal wooden tower located about 100 yards east of the 1771 tower. I.W.P Lewis, a civil engineer, inspected the lighthouse in 1842 and reported it to be in excellent condition. Lewis also mentioned that with the construction of the Whaleback Lighthouse off the coast of Portsmouth, the Portsmouth Harbor Lighthouse could be reduced to 55 feet. The lowering took place in 1851. The tower was outfitted with a Fourth Order Fresnel lens in 1854.
The second tower eventually deteriorated and needed to be replaced. On the original foundation as the 1804 tower, a new 48-foot cast-iron, brick-lined lighthouse tower was built in 1878. When the new tower was finished, the remnants of the 1804 building were demolished. The current light has a constant green signal that can be seen for 12 nautical miles. An acrylic cylinder that encircles the lens turns the light green. The 1903 oil house (restored in 2004) and the 1872 keeper’s house are two other structures that remain at the light station (currently the United States Coast Guard offices).
The lighthouse is currently owned by the United States Coast Guard, but it is maintained by the Friends of Portsmouth Harbor Lighthouses organization. This organization is a chapter of the American Lighthouse Foundation (ALF). ALF has granted the group permission to care for the tower, oil house, and wooden walkway. As of November 2008, the Friends are also in charge of Whaleback Lighthouse. Tours of the lighthouse occur seasonally.
- Originally constructed: 1771
- Current tower constructed: 1878
- First lit: 1878 (current structure)
- Construction: Cast-iron and brick
- Tower shape: Conical
- Height: 48 foot (15 m)
- Focal height: 52 feet (16 m)
- Markings: White with black lantern
- Characteristic: Fixed Green
- Range: 12 nautical miles (22 km; 14 mi)
- Status: Active
- NRHP number: 09000816
- Address: 25 Wentworth Rd
- Town: New Castle
- State: New Hampshire
- GPS: Lat 43.07107 Lng -70.70861
- Parking notes: The lighthouse is located within Coast Guard property. When the gate is open, visitors can park for free near the lighthouse. When the gate is closed, there are other viewing places. Great Island Common and New Castle Beach in New Castle are great nearby viewpoints!
- Parking directions: HERE
- Location directions: HERE