New Hampshire Route 4 is a 3.78 mi state highway located in eastern Strafford County, New Hampshire. Its western terminus is at an intersection with New Hampshire Route 9 and New Hampshire Route 108 in Dover. Its northern terminus is at the Maine state border in Rollinsford, where it continues as Maine State Route 4.
Maine State Route 4 is the same length as New Hampshire Route 4
The New Hampshire Route 4 is 3.78 miles long but it is not stated that Maine State Route 4 is the accounted for in that.