| State: | NH |
| Type: | NH |
| Route: | 13 |
| Map Custom: | yes |
| Map Alt: | Map of New Hampshire Route 13 |
| Map Notes: | Map of southern New Hampshire with NH 13 highlighted in red |
| Length Mi: | 43.368 |
| Direction A: | South |
| Terminus A: | in Townsend, MA |
| Junction: | in Milford in Concord |
| Direction B: | North |
| Terminus B: | in Concord |
| Counties: | Hillsborough, Merrimack |
| Previous Type: | NH |
| Previous Route: | 12A |
| Next Type: | NH |
| Next Route: | 16 |
New Hampshire Route 13 is a 43.38miles long north–south state highway in the state of New Hampshire, United States. The highway runs from Brookline to Concord.
The southern terminus is at the Massachusetts state line in Brookline, where the route continues south as Massachusetts Route 13. The northern terminus is in the center of Concord at U.S. Route 202 and New Hampshire Route 9, locally the intersection of South Street and Pleasant Street.
NH 13 begins as a continuation of Massachusetts Route 13 at the state line between Brookline and Townsend, Massachusetts. It continues north for about 8.4miles through Brookline and crosses into Milford, where it meets an interchange with New Hampshire Route 101. The highway continues north for about 1.4miles through the outskirts of Milford's urban center until it reaches Union Square, better known as the Milford Oval, where it intersects New Hampshire Route 101A.
NH 13 continues north over the Souhegan River on the Colonel John Shepard Bridge, then turns northwest for 4.4miles towards Mont Vernon and serves as the town's main road. After intersecting the Francestown Turnpike in the center of Mont Vernon, NH 13 continues northwest for about 5.9miles until it intersects New Hampshire Route 136 in the center of New Boston. The highway then turns east, crossing the South Branch Piscataquog River, then goes northeast for 6.4miles along the path of the river toward Goffstown. It turns north at the intersection of New Hampshire Route 114 with which it briefly runs concurrently over the Piscataquog River and into downtown Goffstown.
After separating from NH 114 at the Goffstown Public Library, NH 13 continues north for 6.1miles to the town center of Dunbarton, then for another 3.5miles north where it intersects New Hampshire Route 77. After taking a sharp right at the intersection, NH 13 heads northeast towards Concord for 4miles until it reaches the interchange with Interstate 89 near a New Hampshire State Police barracks. NH 13 then turns north on South Street near downtown Concord, where it meets its northern terminus at US 202/NH 9.