Question: New Hampshire Route 31 begins in which Hillsborough County, New Hampshire town?

Context paragraphs:
Mason, New Hampshire: Mason is a town in Hillsborough County, New Hampshire, United States.  The population was 1,382 at the 2010 census.  Mason, together with Wilton, is home to Russell-Abbott State Forest.

New Hampshire Route 140: New Hampshire Route 140 is a 21.142 mi east–west state highway in central New Hampshire, running from Tilton to Alton.  The western terminus of NH 140 is in Tilton at an intersection with U.S. Route 3, New Hampshire Route 11 and New Hampshire Route 132, located at exit 20 on Interstate 93.  The eastern terminus is in Alton at NH 11 and New Hampshire Route 28A (Main Street).  In Alton, the road is named the Frank C. Gilman Highway.

New Hampshire Route 4: 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.

New Hampshire Route 27: New Hampshire Route 27 (abbreviated NH 27) is a 37.621 mi long east–west highway in southeastern New Hampshire.  The western terminus of NH 27 is in Hooksett at U.S. Route 3 and New Hampshire Route 28 north of Manchester.  The eastern terminus is in Hampton Beach at New Hampshire Route 1A, which runs along the New Hampshire coastline adjacent to the Atlantic Ocean.

Antrim, New Hampshire: Antrim is a town in Hillsborough County, New Hampshire, United States.  The population was 2,637 at the 2010 census.  The primary settlement in the town, where 1,397 people resided at the 2010 census, is defined as the Antrim census-designated place (CDP) and is located at the intersection of U.S. Route 202 and New Hampshire Route 31.  The town of Antrim also includes the villages of Antrim Center, North Branch, Clinton Village and South Village.

New Hampshire Route 202A: New Hampshire Route 202A (abbreviated NH 202A) is a 14.639 mi east–west state highway in Strafford and Rockingham counties in southeastern New Hampshire.  The western terminus is in Northwood at U.S. Route 202 and New Hampshire 9, near their intersection with U.S. Route 4.  Its eastern terminus is in downtown Rochester at New Hampshire Route 108 and New Hampshire Route 125.

New Hampshire Route 120: New Hampshire Route 120 is a 26.928 mi secondary north–south state highway in Sullivan and Grafton counties in the upper Connecticut River Valley region of New Hampshire.  Its southern terminus is at New Hampshire Route 11 and New Hampshire Route 103 in Claremont.  Its northern terminus is at New Hampshire Route 10 in Hanover.

New Hampshire Route 153: New Hampshire Route 153 is a 50.566 mi secondary north–south highway in Strafford and Carroll counties in eastern New Hampshire.  The southern terminus is in Farmington at New Hampshire Route 11.  The northern terminus is in Conway village (town of Conway) at New Hampshire Route 16 and New Hampshire Route 113.

New Hampshire Route 78: New Hampshire Route 78 (abbreviated NH 78) is a 3.456 mi secondary state highway in Cheshire County in the southern part of the U.S. state of New Hampshire.  A northward extension of Massachusetts Route 78, NH 78 runs entirely within the town of Winchester from the state border to downtown, where it ends at New Hampshire Route 10 and New Hampshire Route 119.

New Hampshire Route 31: New Hampshire Route 31 (abbreviated NH 31) is a 56.148 mi north–south state highway in southern New Hampshire.  It runs from Mason on the Massachusetts border to Goshen.

Supporting paragraphs: New Hampshire Route 31 Mason, New Hampshire
Answer: Mason