[3] The source of the South Branch is the outflow from Budd Lake, a glacial remnant located a few miles northeast of Hackettstown.

[3] At its end, it forms the border between Branchburg and Hillsborough Townships and, upon reaching the border of Bridgewater Township, joins the North Branch Raritan River to form the Raritan River, which generally flows eastward from that point.

In the 1970s, the state discussed plans for a Raritan Confluence Reservoir, which have been shelved due to acquisition costs.

Their mission is to “Protect the Water Resources of the South Branch of the Raritan River and its Watershed”.

Both North and South branches of the Raritan run nearly parallel southwards, east and west of one another, but receive their names from the direction each one flows from at their confluence.