Portsmouth, New Hampshire, is a historic seaport town on the Piscataqua River in Rockingham County, notable for its dense colonial-era street pattern, preserved waterfront neighborhoods, and a concentration of notable sites such as Strawbery Banke, The Hill, and the Gov John Langdon Mansion; its downtown mixes early streetscapes with later commercial blocks and anchors a walkable core that links shops, restaurants, and heritage landmarks across one of New England's oldest urban settlements. - AsNotedIn