In Morris County, the communities of Milton,[7] Petersburg, and Woodstock are within the Oak Ridge CDP.

[1] The Pequannock River, forming the Passaic/Morris county line, takes a winding course through the northern part of the CDP, separating Oak Ridge proper from the communities of Milton and Petersburg.

Oak Ridge Reservoir on the Pequannock lies on part of the northwest border of the CDP.

Bowling Green Mountain, elevation 1,380 feet (420 m), borders the community to the southwest.

[11] The postal addresses within the CDP, including the communities within Jefferson Township, read "Oak Ridge, New Jersey".