New Boston is a town in Hillsborough County, New Hampshire, United States. The population was 5,321 at the 2010 census. New Boston is home to the annual Hillsborough County Agricultural Fair and the Molly Stark Cannon.
The town was first granted in 1736 by colonial governor Jonathan Belcher of Massachusetts and New Hampshire. At the time, lands to the west of the Merrimack River, disputed between the two provinces, were treated by Belcher as part of Massachusetts, and he granted the town to several Boston families. It was to have been called Lanestown or Piscataquog Township, but by 1751 they called it New Boston after their hometown. Not all the grantees took up their claims, and the land was regranted 10 years later to settlers from Londonderry. When the town was incorporated in 1763, Governor Benning Wentworth formally recognized the long-used name of New Boston.
In 1820, the town had 25 sawmills, six grain mills, two clothing mills, two carding mills, two tanneries and a bark mill. It also had 14 schoolhouses and a tavern. The Great Village Fire of 1887, which started when a spark from a cooper's shop set a barn on fire, destroyed nearly 40 buildings in the lower village.