Southsea is a seaside resort and geographic area, located in Portsmouth at the southern end of Portsea Island, Hampshire, England. Southsea is located to the south of Portsmouth city centre and to the east of Old Portsmouth. It developed as a fashionable Victorian seaside resort in the 19th century, originally named Croxton Town, but later borrowed the name of nearby Southsea Castle to promote itself and grew into a dense residential suburb and large distinct commercial and entertainment area, separate from the centre of Portsmouth. The 'Southsea' name of the area originates from Southsea Castle; a fort, located on the seafront and constructed in 1544 to help defend the Solent and approaches to Portsmouth Harbour