Sullivan's Island lies to the north of the entrance and Morris Island to the south.
The entrance itself is about 1 mile (2 km) wide; it was originally only 18 feet (5 m) deep, but began to be enlarged in the 1870s.
Charleston was founded in 1670 as Charles Town, honoring King Charles II of England.
Its initial location at Albemarle Point on the west bank of the Ashley River (now Charles Towne Landing) was abandoned in 1680 for its present site, which became the fifth-largest city in North America within ten years.
These cities combined with other incorporated and unincorporated areas along with the city of Charleston form the Charleston-North Charleston Urban Area with a population of 548,404 as of 2010 The metropolitan statistical area also includes a separate and much smaller urban area within Berkeley County, Moncks Corner (with a 2000 population of 9,123). II was restored to the English throne in 1660, he granted the chartered Province of Carolina to eight of his loyal friends, known as the Lords Proprietors, on March 24, 1663.