It is considered one of the Sea Islands in the Lowcountry region and is the most populous island in northern Beaufort County, containing most of the incorporated areas of Beaufort, Port Royal, and other unincorporated communities.

The island takes its name from the Port Royal Sound, a historically significant harbor during colonial settlement in the 16th, 17th, and 18th centuries.

[1] During the English colonization of Carolina, the English adopted the name Port Royal for the sound and for the present-day Parris Island once their colonization efforts began, with the establishment of Charles Town in 1670.

Historically, the island has been predominantly agricultural and had been developed as plantations in the antebellum years.

Since the 1960s, the island has become mostly residential and commercial in character, though rural areas continue to exist in the extreme northern and western portions of the island along the Whale Branch River.