Middlebrook is an unincorporated community within the borough of Bound Brook in Somerset County, in the U.S. state of New Jersey.

It is named after the Middle Brook, a tributary of the Raritan River, on the western side of the community.

[4] On September 25, 1683, Thomas Codrington, one of the original group, was apportioned 877 acres of this tract and built a house here, which he called Rackawackhana.

[5] After the Battle of Bound Brook on April 13, 1777, General George Washington moved the Continental Army from its winter encampment at Morristown to the Middle Brook valley between the First and Second Watchung Mountains, now called Washington Valley, protected by positions on the Middlebrook Heights,[6] the First Watchung ridge north of Middlebrook.

[7][8] The Harris Tavern, built 1700 at the intersection of West Main Street and Vosseller Avenue, was the first hotel in Bound Brook.