Hyde Park is one of the largest parks in London and one of its Royal Parks. The park is the largest of four that form a chain from the entrance of Kensington Palace through Kensington Gardens and Hyde Park, via Hyde Park Corner and Green Park past the main entrance to Buckingham Palace and on through Saint James's Park to Horse Guards Parade in Whitehall. The park is divided by the Serpentine and the Long Water.
The park is contiguous with Kensington Gardens which are often assumed to be part of Hyde Park; Kensington Gardens has been separate since 1728, when Queen Caroline divided them. Hyde Park covers 142 hectares (350 acres) and Kensington Gardens covers 111 hectares (275 acres), giving a total area of 253 hectares (625 acres), making their combined area larger than the Principality of Monaco (196 hectares or 480 acres), though smaller than the Bois de Boulogne in Paris (845 hectares, or 2090 acres), New York City's Central Park (341 hectares or 840 acres), and Dublin's Phoenix Park (707 hectares, or 1,750 acres). To the southeast, outside the park, is Hyde Park Corner. During daylight, the two parks merge seamlessly into each other but Kensington Gardens closes at dusk and Hyde Park remains open throughout the year from 5 a.m. until midnight.
The Great Exhibition of 1851 was held in the park, for which the Crystal Palace, designed by Joseph Paxton, was erected. The park became a traditional location for mass demonstrations. The Chartists, the Reform League, the suffragettes, and the Stop the War Coalition have all held protests there. Many protesters on the Liberty and Livelihood March in 2002 started their march from Hyde Park.
Hyde Park is also a ward of the City of Westminster. The population of the ward at the 2011 Census was 12,462.