This territory was first granted by the Massachusetts government in 1736 as No. 3, the third in a line of settlements along the east side of the Connecticut River which was sometimes called Great Falls. In 1752, Governor Benning Wentworth granted the territory to Benjamin Bellows and others as Walpole in honor of Sir Robert Walpole, first Prime Minister of England. Colonel Benjamin Bellows, for whom Bellows Falls, Vermont, was named, built a large fort at Walpole for defense against Indian attack, and had surveyed most of the Connecticut River towns. The grant was renewed in 1781 due to the Indian wars making completion of grant terms impractical.
Population change for Walpole totaled 1,045 over 56 years, from 2,825 in 1960 to 3,870 in 2016. The largest decennial percent change was an increase of 12 percent between 1990 and 2000; percent change over the three previous decades were all below ten percent. The 2016 Census estimate for Walpole was 3,870 residents, which ranked 98th among New Hampshire's incorporated cities and towns. (info from NHES website)