borough (district), administrative county of West Sussex, historic county of Sussex, England, on the English Channel. Road and railway links to London, 58 miles (93 km) northwest, have spurred Worthing's growth as a seaside resort and as a residential town for retired people. Its mild and notably sunny climate also favours the cultivation of salad crops in the vicinity. Area 12 square miles (32 square km). Pop. (2001) 97,540.