Georgetown, Guyana. Georgetown is the capital and largest city of Guyana. It is situated in Demerara-Mahaica, region 4, on the Atlantic Ocean coast, at the mouth of the Demerara River. It is nicknamed the "Garden City of the Caribbean.". It is the retail, administrative, and financial services centre of the country, and the city accounts for a large portion of Guyana's GDP. The city recorded a population of 118,363 in the 2012 census.