The North Branch begins in a highland region of lakes, swamps, and intricate stream networks in the town of Stoddard, New Hampshire.

Geographic Names Information System places the beginning of the North Branch at the outlet of Robb Reservoir in the southeast corner of Stoddard.

[1] Additional significant flow quickly arrives when the outlet of Highland Lake and Island Pond joins from the north.

Below Franklin Pierce Lake it is a short distance to the Contoocook River in Hillsborough.

Beards Brook enters the North Branch in Hillsborough just upstream of the river's end at the Contoocook.