Portsmouth is a city in Rockingham County, New Hampshire, United States. At the 2020 census it had a population of 21,956. A historic seaport and popular summer tourist destination on the Piscataqua River bordering the state of Maine, Portsmouth was formerly the home of the Strategic Air Command’s Pease Air Force Base, since converted to Portsmouth International Airport at Pease.

American Indians of the Abenaki and other Algonquian languages-speaking nations, and their predecessors, inhabited the territory of coastal New Hampshire for thousands of years before European contact.

The first known European to explore and write about the area was Martin Pring in 1603. The Piscataqua River is a tidal estuary with a swift current, but forms a good natural harbor. The west bank of the harbor was settled by European colonists in 1630 and named Strawbery Banke, after the many wild strawberries growing there. The village was protected by Fort William and Mary on what is now New Castle Island. Strategically located for trade between upstream industries and mercantile interests abroad, the port prospered. Fishing, lumber and shipbuilding were principal businesses of the region. Enslaved Africans were imported as laborers as early as 1645 and were integral to building the city’s prosperity. Portsmouth was part of the Triangle Trade, which made significant profits from slavery.

At the town’s incorporation in 1653, it was named “Portsmouth” in honor of the colony’s founder, John Mason. He had been captain of the English port of Portsmouth, Hampshire, after which New Hampshire is named.

When Queen Anne’s War ended in 1712, Governor Joseph Dudley selected the town to host negotiations for the 1713 Treaty of Portsmouth, which temporarily ended hostilities between the Abenaki Indians and the colonies of Massachusetts Bay and New Hampshire.

In 1774, in the lead-up to the Revolution, Paul Revere rode to Portsmouth warning that the British Royal Navy was coming to capture the port. Although Fort William and Mary protected the harbor, the Patriot government moved the capital inland to Exeter, which ensured that it would be under no threat from the Royal Navy, which bombarded Falmouth (now Portland, Maine) instead on October 18, 1775. Portsmouth was the destination for several of Beaumarchais’s ships containing materiel, such as artillery, tents, and gunpowder, to help the American revolutionary effort. African Americans helped defend Portsmouth and New England during the war. In 1779, 19 enslaved African Americans from Portsmouth wrote a petition to the state legislature and asked that it abolish slavery, in recognition of their war contributions and in keeping with the principles of the Revolution. Their petition was not answered, but New Hampshire later abolished slavery.

Thomas Jefferson’s 1807 embargo against American trade with Britain severely disrupted New England’s trade with Canada, and several local businessmen went bankrupt. Portsmouth was host to numerous privateers during the War of 1812. In 1849, Portsmouth was incorporated as a city.