Settled by citizens from Haverhill, Massachusetts, the town was first known as "Lower Coos." It was incorporated in 1763 by Colonial Governor Benning Wentworth. In 1773, Haverhill became the county seat of Grafton County. It was the terminus of the old Province Road, which connected the northern and western settlements with the seacoast. The town is home to the oldest documented covered bridge in the country still standing -- the Haverhill-Bath Bridge, built in 1829.
The village of Woodsville, named for John L. Woods of Wells River, Vermont, was once a very important railroad center. Woods operated a sawmill on the Ammonoosuc River, and developed a railroad supply enterprise following the establishment of the Boston, Concord and Montreal Railroad. The village of Pike was settled by future employees of the Pike Manufacturing Company, which was, for a time, the world's leading manufacturer of whetstones.
Woodsville served as the county seat until 1972, when Grafton County administrative offices were moved to rural land halfway between Woodsville and the smaller village of North Haverhill.
As of the census of 2000, there were 4,416 people, 1,755 households, and 1,147 families residing in the town. The population density was 86.5 people per square mile (33.4/km²). There were 2,148 housing units at an average density of 42.1/sq mi (16.2/km²). The racial makeup of the town was 98.23% White, 0.45% African American, 0.25% Native American, 0.36% Asian, 0.02% Pacific Islander, 0.20% from other races, and 0.48% from two or more races. Hispanic or Latino of any race were 0.61% of the population.
There were 1,755 households out of which 28.3% had children under the age of 18 living with them, 52.6% were married couples living together, 8.7% had a female householder with no husband present, and 34.6% were non-families. 27.9% of all households were made up of individuals and 12.9% had someone living alone who was 65 years of age or older. The average household size was 2.38 and the average family size was 2.91.
In the town the population was spread out with 23.6% under the age of 18, 7.5% from 18 to 24, 26.6% from 25 to 44, 24.6% from 45 to 64, and 17.6% who were 65 years of age or older. The median age was 40 years. For every 100 females there were 99.5 males. For every 100 females age 18 and over, there were 94.1 males.
The median income for a household in the town was $36,853, and the median income for a family was $44,816. Males had a median income of $27,100 versus $23,828 for females. The per capita income for the town was $17,465. About 6.4% of families and 6.8% of the population were below the poverty line, including 6.1% of those under age 18 and 6.0% of those age 65 or over.