Limerick is a city and the county seat of County Limerick in the Province of Munster, in the midwest of the Republic of Ireland. The city lies on the River Shannon; the population is approximately 54,000. The city center is divided between the traditional areas of English Town on the south side of Kings Island, (which includes a castle), Irish Town (which includes the older streets on the south bank), and the current economic center, called Newtown Perry. Newtown Perry was build in the late 18th century and the area is laid out on a grid plan. Georgian architecture is evident in the city from the 1800s. Although some has been demolished, much of the area is built in the same Georgian fashion. Other architectural marvels are King John's Castle and St. Mary's Cathedral, which is over 800 years old, one of the oldest in Ireland. The Hunt Museum is based on the historic 18th century former Custom House. It was established to house an internationally important collection of 2,000 works of art and antiquities formed by the Hunts during their lifetime.