Woodsville is a census-designated place (CDP) in the town of Haverhill in Grafton County, New Hampshire, U.S., along the Connecticut River at the mouth of the Ammonoosuc River. The population was 1,126 at the 2010 census. Although North Haverhill is now the county seat of Grafton County, the village of Woodsville has traditionally been considered the county seat, as the county courthouse was originally located there.