Just north of New Rockford, ND 15 turns east and travels about 25 miles (40 km) across nearly all of Eddy County to begin a concurrency with ND 20.

3 miles (4.8 km) farther east, the route enters Nelson County.

The route heads 8 miles (13 km) east during this concurrency, passing through Northwood.

[8] Between just east of Pekin and the south side of Northwood, the highway stair-stepped along through Nelson and Grand Forks counties.

[7] To reduce the number of turns, the stair-stepping portion of the highway was straightened into a diagonal and a new alignment was built that passed to the north of Northwood.