Strategically located for trade between upstream industries and mercantile interests abroad, the port prospered.Fishing, lumber and shipbuilding were principal businesses of the region.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.
It now serves as the Portsmouth Historical Society Museum.The Portsmouth Naval Shipyard, established in 1800 as the first federal navy yard, is located on Seavey's Island in Kittery, Maine. Though US President Theodore Roosevelt orchestrated the peace conference that brought Russian and Japanese diplomats to Portsmouth and the Shipyard, he never came to Portsmouth, relying on the Navy and people of New Hampshire as the hosts.Roosevelt won the 1906 Nobel Peace Prize for his diplomacy in bringing about an end to the War. The city announced construction of a 600-space garage, the city's second downtown parking garage, to begin in April or May 2017. Route 4, New Hampshire Route 1A, New Hampshire Route 16, and New Hampshire Route 33.African Americans helped defend Portsmouth and New England during the war.In 1779, 19 slaves 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.Portsmouth annually celebrates the revitalization of its downtown (in particular Market Square) with Market Square Day, a celebration dating back to 1977, produced by the non-profit Pro Portsmouth, Inc.Portsmouth shipbuilding history has had a long symbiotic relationship with Kittery, Maine, across the Piscataqua River.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.The highest point in the city is 110 feet (34 m) above sea level, within Pease International Airport. Summers are moderately warm with winter days averaging around the freezing point, but with cold nights bringing it below the required −3 °C (27 °F) isotherm to have a humid continental climate.With high year-round precipitation, the cold winters can often be very snowy and summers wet.