Hillsborough Township is a township in Somerset County. Hillsborough is a collection of small villages, each of which has left its own imprint on the Townships history: Belle Mead, Blackwells Mills, Flagtown, Neshanic amd South Branch. The township borders Branchburg Township, Bridgewater Township, Franklin Township, Manville, Millstone, Montgomery Township, Raritan and Somerville in Somerset County; and East Amwell Township, Raritan Township and Readington Township in Hunterdon County.

Hillsborough has a very successful record of preserving thousands of acres from development. This is one of the many reasons why Hillsborough is one of the best places to live in the United States.

Hillsborough is home to Duke Gardens and Duke Farms, a 2,700 acres estate in the north-eastern quadrant of the town that was originally owned by tobacco and electric energy tycoon James "Buck" Duke and then passed down to daughter Doris Duke, and is now one of the few remaining "preserved" natural areas in Hillsborough Township.

U.S. Route 206 is the main road that passes through the township. Main county roads that pass through are CR 514 and CR 533. Interstate 287 is outside the municipality in bordering Bridgewater and Franklin Townships.