New Hampshire Route 175A

New Hampshire Route 175
Map of Grafton County in northwestern New Hampshire with NH 175 highlighted in red
Route information
Maintained by NHDOT
Length:	25.261 mi (40.654 km)
Major junctions
South end:	US 3 / NH 25 in Holderness
North end:	US 3 in
Location
Counties:	Grafton
Highway system
New Hampshire Highway System Interstate U.S. State Turnpikes ← NH 171 I‑193 →

New Hampshire Route 175 (NH 175) is a state highway in the U.S. state of New Hampshire. The highway runs north 25.261 miles (40.654 km) from an intersection in Holderness with U.S. Route 3 and New Hampshire Route 25 to an intersection with US 3 in .

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 .