Port Royal is an unincorporated community on the border of Montgomery and Robertson counties, Tennessee. It is home to Port Royal State Park and is located at the confluence of the Red River and Sulphur Fork Creek.

Montgomery County is a county in the U.S. state of Tennessee. As of the 2020 United States census, the population was 220,069. The county seat is Clarksville. The county was created in 1796. Montgomery County is included in the Clarksville, TN–KY Metropolitan Statistical Area.