RSA 231:51: Dedicated Ways.

Any street, lane or alley within this state which has been dedicated to public use by being drawn or shown upon a plan of lands platted by the owner, and the sale of lots in accordance with such plan, may be released and discharged from all public servitude by vote of the governing body of a city or town if such street, lane, or alley has not been opened, built, or used for public travel within 20 years from such dedication.