Page "Bridgewater Township, New Jersey" Paragraph 8

The Raritan River and its branches and tributaries form much of Bridgewater's borders with other municipalities and a number of smaller rivers and streams run through Bridgewater.

The Raritan itself runs along Bridgewater's southern border ( except where Somerville and Raritan were carved out as separate boroughs ) and the North Branch of the Raritan River forms the township's western border with Branchburg.

The North Branch and South Branch of the Raritan River meet at the extreme southwestern corner of Bridgewater at the border with both Branchburg Township and Hillsborough Township, and this point known as the Raritan River Confluence was once intended to be a major reservoir.