Portsmouth Naval Shipyard 

Kittery, Maine 

Cultural Resources Fact Sheet 

Location 

Portsmouth Naval Shipyard (PNSY) is located in the 

Town of Kittery, Maine at the southernmost tip of the 

state, and is approximately 50 miles from Boston, Massachusetts, Portland, Maine, and Manchester, New Hampshire. PNSY occupies approximately 280 acres on 

Seavey Island, situated at the mouth of the Piscataqua 

River between Portsmouth, New Hampshire and Kittery, 

Maine. 

Mission 

Established on June 12, 1800 as one of the six original 

naval shipyards, Portsmouth is the Nation’s oldest continuously operating Naval Shipyard. Originally developed to 

build wooden ships for the Navy’s Fleet, the shipyard’s 

mission evolved as technologies changed. During World 

War I, PNSY took on a new and important role, the construction of submarines-in addition to the overhaul and 

repair of surface vessels. Portsmouth continued to build 

Portsmouth Naval Shipyard — Cultural Resources Fact Sheets pg. 1 

submarines until 1969. Today, Portsmouth’s primary mission is the overhaul, repair and modernization of submarines. Portsmouth Naval Shipyard provides the U.S. Navy’s nuclear powered submarine fleet with quality overhaul work in a safe, timely and affordable manner. 

Approximately 6,500 civilian employees currently work at 

PNSY, along with 1,000 active duty military personnel 

assigned to the Shipyard and Installation, submarine and 

Coast Guard cutter crews and an additional 1,000 civilians assigned to tenant commands. Although PNSY functions primarily as an industrial facility for the overhauling 

of submarines, it also provides support facilities for the 

U.S. Navy Survival, Evasion, Resistance, & Escape 

(SERE) School, the Naval Branch Health Clinic Portsmouth, U.S. Army New England Recruiting Battalion, the 

Defense Logistics Agency, and the U.S. Coast Guard. 

PNSY also supports military personnel with on-base 

berthing, family-oriented programs, and recreational opportunities. 

Figure 1. Present-Day View of the Portsmouth Naval Shipyard 
Portsmouth Naval Shipyard — Cultural Resources Fact Sheets pg. 2 

 Portsmouth Naval Shipyard Cultural Resources Fact Sheet

History 

Located on what were originally five islands at the mouth 

of the Piscataqua River, Portsmouth Naval Shipyard 

(PNSY) was established by Congress in 1800. Selected 

for its geographic advantages and the availability of experienced shipbuilders, PNSY began by producing 

wooden ships for the Navy. Evolving with Navy requirements, the Shipyard mission significantly transformed 

during World War I. In 1917, PNSY designed and constructed the L-8, the first government-built submarine. 

Shortly thereafter, in 1923, PNSY was designated as the 

Navy’s primary submarine shipyard. World War II (WWII) 

brought massive expansion to PNSY in support of the 

increased demand for submarines. During WWII, PNSY 

produced 77 submarines, approximately half of the US 

submarine fleet. Following World War II, PNSY was 

named the Navy’s center for submarine design and development. The research submarine, USS Albacore, 

with its revolutionary “tear drop” shaped hull and round 

cross section, was designed and launched at Portsmouth 

in 1953. The Albacore set the standard for all subsequent submarine hull design world-wide. PNSY continued to build submarines until 1969, when the last submarine built in a public shipyard, the USS Sand Lance, was 

launched. The mission was then realigned to function 

exclusively as a submarine overhaul facility. 

The archaeological record indicates that, typical of 

coastal Maine, portions of the Shipyard were used by 

Native Americans as transitory fishing and camping sites 

during the pre-contact and post-contact eras. European 

occupation of the Shipyard islands is documented beginning in the late seventeenth century. The islands were 

used for residential occupation, and may have been used 

for fish drying. As the Navy’s needs changed, they expanded by purchasing nearby islands and filling the areas 

between them to create the one island known today. 

Historic Properties 

The Portsmouth Naval Shipyard Historic District was 

listed in the National Register of Historic Places in 1977, 

and was expanded in 2008 to include two additional eligible districts. The District, which encompasses approximately two-thirds of Seavey Island, contains buildings, 

structures, objects, and archaeological sites with a period 

of significance ranging from 1800 - 1987. While additional criteria are likely applicable, the District was determined to have significance under Criteria A and C. Significant archaeological sites ranging from prehistoric to 

Twentieth-Century Navy-related occupation have also been identified outside of the Historic District. 

Figure 2. Portsmouth Naval Shipyard, 1943

SIOP Nationwide PA, Enclosure 2