| State: | NH |
| Type: | NH |
| Route: | 175 |
| Map Custom: | yes |
| Map Notes: | Map of Grafton County in northwestern New Hampshire with NH 175 highlighted in red |
| Length Mi: | 25.261 |
| Direction A: | South |
| Terminus A: | in Holderness |
| Direction B: | North |
| Terminus B: | in Woodstock |
| Counties: | Grafton |
| Previous Type: | NH |
| Previous Route: | 171 |
| Next Type: | I |
| Next Route: | 193 |
New Hampshire Route 175 (NH 175) is a state highway in the U.S. state of New Hampshire. The highway runs north 25.261miles from an intersection in Holderness with U.S. Route 3 and New Hampshire Route 25 to an intersection with US 3 in Woodstock.
NH 175 is a minor highway that parallels US 3 and Interstate 93 through the valley of the Pemigewasset River. NH 175 has a secondary spur road, NH 175A, which connects it to downtown Plymouth.
NH 175 begins at an intersection with US 3 and NH 25 (Daniel Webster Highway) at Little Squam Lake in the town of Holderness. The state highway heads north and then west through a hilly area where it briefly passes through the town of Ashland before returning to Holderness. NH 175 enters the valley of the Pemigewasset River and passes by the historic Trinity Church and near the Holderness School and the Chapel of the Holy Cross. North of the school and churches, the highway meets the eastern end of its spur into Plymouth and Plymouth State University, NH 175A. NH 175 continues north parallel to the river and I-93 and US 3, which follow the opposite, right bank of the river, into the town of Campton. The highway crosses the Beebe River and parallels the Mad River to its bridge over the river immediately to the south of the highway's junction with NH 49. NH 175 passes through the town of Thornton and its name becomes Eastside Road on entering the town of Woodstock. The highway passes under I-93, has two crossings of the Pemigewasset River, and intersects Tripoli Road, which has a diamond interchange with I-93 immediately to the east. NH 175 has an oblique grade crossing of the Hobo Railroad before crossing the river a third time on a truss bridge and reaching its northern terminus at US 3 (Daniel Webster Highway) just south of the community of North Woodstock.
| State: | NH |
| Type: | NH |
| Route: | 175A |
| Location: | Plymouth–Holderness |
| Length Mi: | 0.806 |
| Length Round: | 2 |
New Hampshire Route 175A (NH 175A) is a 0.806adj=midNaNadj=mid spur route of NH 175 in the towns of Plymouth and Holderness. The highway begins as the east leg of a roundabout in downtown Plymouth, which is dominated by the campus of Plymouth State University. The north and south legs of the roundabout consist of Main Street, which carries US 3 and NH 25; the west leg is town-maintained High Street. NH 175A has a grade crossing of a railroad and crosses over the Pemigewasset River into Holderness. The highway passes through the athletic complex of the university before reaching its four-ramp partial cloverleaf interchange with I-93. East of I-93, NH 175A has its eastern terminus at NH 175.