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Town of Portsmouth
State: NH
County: Rockingham


Piscataqua River Watershed

Sagamore Brook originates in a boggy area, west of a farm on Peverly Hill Road. The brook passes under the road, near several commercial buildings, and then flows into a salt marsh, which sits on both sides of Lafayette Road. Several large businesses border the salt marsh where the brook crosses Lafayette Road. A majority of the land surrounding this marsh is within the New Hampshire Division of Forests and Lands’ Urban Forestry Center. This area is largely undeveloped, in contrast to the rest of Sagamore Brook’s shoreline. The brook flows east from the marsh, and passes through a residential along Route 1A. It flows past numerous homes, businesses, and docks, until it joins the Piscataqua River.

South Mill Pond sits in the heart of downtown Portsmouth. Its entire shoreline is surrounded by development, including several athletic fields and parking lots. Water flowing out of the pond passes under Marcy Street, and then joins the Piscataqua River.

Harvey Brook flows out of a small marsh area, along the New Hampshire Turnpike. It flows north through a narrow strip of landscaped area along the highway and then passes under the Route 4 on ramp. The brook then joins Hodgson Brook in the area between the Spaulding Turnpike and the New Hampshire Turnpike.

Hodgson Brook flows out of the developed area around the former Pease Air Force Base. The brook passes under Corporate Drive, and then turns south along the Spaulding Turnpike. It then flows into the area where several highways converge, passing through culverts under the Spaulding Turnpike, Ashland Avenue, the New Hampshire Turnpike, and Route 1. The brook passes under several smaller roads on the outskirts of downtown Portsmouth, where its shoreline is bordered by numerous businesses and parking lots. Hodgson Brook flows into North Mill Pond which sits along the Boston and Maine Railroad tracks. The eastern shore of this pond is mostly industrial, dominated by railroad facilities, while the western shore is mostly residential, with many homes and a park. The pond water flows out of the pond, under a bridge on Route 1, and joins the Piscataqua River.

The Piscataqua River forms Portsmouth’s eastern border with Maine. Its shoreline is completely developed, beginning with the Pease International Trade Port terminals, and changing to apartment buildings and marinas as it passes downtown Portsmouth. The river flows around several developed islands as it passes downtown and flows under the bridge on New Castle Avenue. Marshes and mud flats form along the shoreline as the river approaches its mouth. The Piscataqua River passes into New Castle on its way to the Gulf of Maine.

To see the locations of these resources in Google Earth follow this link.

If you do not have Google Earth software you may download it by following this link.

Water District: Portsmouth PWD, Water Division
District Website: http://www.cityofportsmouth.com/publicwo...
Water Source: Bellamy river, groundwater wells
# Accts Serv: 9,000?
Other Towns: Newington
Sewer District: Portsmouth Sewer Division
District Website: http://www.cityofportsmouth.com/publicwo...
Receiving Waters: Piscatagua River
# Accts Serv: 20786 pop.
Other Towns: none
(Click the Title of the article to learn more.)
Great Bay National Estuarine Research Reserve
Community Assistance Providers
Provides education, outreach, research, and stewardship in support of estuaries and rivers.

Portsmouth Master Plan
Publications, Websites, and Tools
The 2005 update to the Portsmouth Master Plan.

Southeast Land Trust of New Hampshire
Community Assistance Providers
A regional land trust serving 39 communities in southeastern New Hampshire

Seal:town seal, click to enlarge
Population:20618 (U.S. Census Est. 2006)
Area:15.7 square miles


Portsmouth’s land use pattern is well established, with little remaining undeveloped land. This will have an influence on future growth in the city, and put pressure on the few remaining areas of open space. The population of Portsmouth was estimated at 20,618 in 2006. Based on census projections, Portsmouth is predicted to grow to 21,990 by 2015, which represents a growth rate of approximately 6.5%.

Without question, Portsmouth enjoys a healthy economy, with a diversity of businesses meeting the needs of local residents. Moreover, with the growth of Pease as an industrial and business center over the past decade, Portsmouth has also become a major source of employment in the Seacoast region. While almost half of the City’s working residents are employed locally, nearly 80 percent of the employees in Portsmouth businesses commute in from other communities.

Portsmouth is pursuing some trail and path initiatives which include completion of the Piscataqua Riverwalk along a portion of the Bow Street waterfront, development of trails and overlooks at Pierce Island, and long range planning for a North Mill Pond pedestrian and bike pathway. Portsmouth manages a number of small parcels of conservation land including areas around Sagamore Creek and the Great Bog. Large conservation parcels are also held under a private easement on the Great Bog and by the state at the Urban Forestry Center.

Occupying 16 percent of Portsmouth’s land area, the Pease International Tradeport includes a number of important habitat types (such as an endangered plant species) as well as environmental challenges, yet it is not subject to the City’s land use regulations. Prior air base operations resulted in extensive contamination of groundwater and stream systems in both the Great Bay and Hodgson Brook watersheds.

to learn more see The Portsmouth Master Plan


Explorers began arriving to the Portsmouth area in 1603. It would be settled in 1630 as Piscataqua, then given the name Strawbery Banke because of abundant wild strawberries growing beside the Piscataqua River. Strategically located for trade between various upstream industries (particularly logging) and mercantile interests abroad, the port prospered. Fishing, lumber and shipbuilding were principal businesses.

The town was incorporated in 1653. In 1679, Portsmouth became the colonial capital.

During President Thomas Jefferson's 1807 embargo, which withered trade, a number of local fortunes were lost. Others were gained by privateering during the War of 1812. In 1849, Portsmouth incorporated as a city.

Fires devastated Portsmouth in the early 19th century, the worst being in 1813 when 244 buildings burned.

Portsmouth was once one of the nation's busiest ports and shipbuilding cities. Not having any major water powers, Portsmouth was left behind by other New Hampshire towns during the industrial revolution and did not experience the same prosperity and rapid growth at that time. Shipbuilding and fishing continued during the late 1800’s and into the 1900’s. During the mid 1900’s tourism grew as an industry for Portsmouth which has retained much of its historic character. The establishment of the Pease Airforce base in the 1950’s played a major role in the development of Portsmouth. The city also maintained its importance for trade and shipping in the 1990’s with the establishment of the Pease International Tradeport.

Portsmouth Waterfront
Scott Richardson
The Wells National Estuarine Research Reserve at Laudholm Farm, Wells, Maine Copyright 2006 All rights reserved. Collaboration with NOAA CSC, Charleston SC