New Hampshire's 3rd State Senate district is one of 24 districts in the New Hampshire Senate. It has been represented by Republican Mark McConkey since 2024.
District 3 covers all of Carroll County as well as small portions of Coos, Grafton and Strafford Counties in the central-eastern portion of the state. It includes the towns of Albany, Bartlett, Brookfield, Chatham, Conway, Eaton, Effingham, Freedom, Hale's Location, Hart's Location, Jackson, Madison, Moultonborough, Ossipee, Sandwich, Tamworth, Tuftonboro, Wakefield, and Wolfeboro in Carroll County; Waterville Valley in Grafton County; and Middleton and Milton in Strafford County. It also comprises a few mostly uninhabited and unincorporated townships in souther Coos County.
The district is located almost entirely within New Hampshire's 1st congressional district, with a small portion extending into the 2nd congressional district. It borders the state of Maine.