The South Branch of the Israel River is a 6.8-mile-long (10.9 km)[1] river in the White Mountains of New Hampshire in the United States. It is a tributary of the Israel River and part of the Connecticut River watershed. For most of its length, it is within the White Mountain National Forest.
The South Branch rises on the western slopes of Mount Jefferson in the Presidential Range of the White Mountains. It flows west, between the Ridge of the Caps to the south and Castellated Ridge to the north, then turns northwest when it reaches the Jefferson Notch Road. The river parallels the notch road and enters the town of Jefferson, where it joins the Israel River.