The park is divided in two by the Serpentine Lake. The park is contiguous with Kensington Gardens; although often still assumed to be part of Hyde Park, Kensington Gardens has been technically separate since 1728, when Queen Caroline made a division between the two. Hyde Park is 350 acres (140 hectare/1.4 km²) and Kensington Gardens is 275 acres (110 ha/1.1 km²) giving an overall area of 625 acres (250 ha/2.5 km²), making this park larger than the Principality of Monaco (1.96 square kilometres or 485 acres), but still smaller than Central Park (3.41 square kilometres or 843 acres). To the southeast (but outside of the park) is Hyde Park Corner. Although, during daylight, the two parks merge seamlessly into each other, Kensington Gardens closes at dusk but Hyde Park remains open throughout the year from 5 am until midnight.
The park has become a traditional location for mass demonstrations. The Chartists, the Reform League, the Suffragettes and the Stop The War Coalition have all held protests in the park. Many protestors on the Liberty and Livelihood March in 2002 started their march from Hyde Park.
On 20 July 1982 in the Hyde Park and Regents Park bombings, two bombs linked to the Provisional Irish Republican Army caused the death of eight members of the Household Cavalry and the Royal Green Jackets and seven horses.
In 1536 Henry VIII acquired the manor of Hyde from the canons of Westminster Abbey, who had held it since before the Norman Conquest; it was enclosed as a deer park and used for hunts. It remained a private hunting ground until James I permitted limited access to gentlefolk, appointing a ranger to take charge. Charles I created the Ring (north of the present Serpentine boathouses) and in 1637 he opened the park to the general public.
In 1689, when William III moved his habitation to Nottingham House in the village of Kensington on the far side of Hyde Park, and renamed it Kensington Palace, he had a drive laid out across its south edge, leading to St. James's Palace; this Route du Roi came to be corrupted to Rotten Row, which still exists as a wide straight gravelled carriage track leading west from Hyde Park Corner across the south boundary of Hyde Park. Public transportation that was entering London from the west paralleled the King's private road along Kensington Gore, just outside the Park.
The first coherent landscaping was undertaken by Charles Bridgeman for Queen Caroline; under the supervision of Charles Withers, Surveyor-General of Woods and Forest, who took some credit for it, it was completed in 1733 at a cost to the public purse of ₤20,000. Bridgeman's piece of water called The Serpentine, formed by damming the little Westbourne that flowed through the Park was not truly in the serpentine "line of beauty" that William Hogarth described, but merely irregular on a modest curve. The 2nd Viscount Weymouth was made Ranger of Hyde Park in 1739 and shortly began digging the serpentine lakes at Longleat. The Serpentine is divided from the Long Water by a bridge designed by George Rennie (1826).
One of the most important events to take place in the park was the Great Exhibition of 1851. The Crystal Palace was constructed on the south side of the park. The public in general did not want the building to remain in the park after the conclusion of the exhibition, and the design architect, Joseph Paxton, raised funds and purchased it. He had it moved to Sydenham Hill in South London.
"It consists of a screen of handsome fluted Ionic columns, with three carriage entrance archways, two foot entrances, a lodge, etc. The extent of the whole frontage is about 107 ft (33 m). The central entrance has a bold projection: the entablature is supported by four columns; and the volutes of the capitals of the outside column on each side of the gateway are formed in an angular direction, so as to exhibit two complete faces to view. The two side gateways, in their elevations, present two insulated Ionic columns, flanked by antae. All these entrances are finished by a blocking, the sides of the central one being decorated with a beautiful frieze, representing a naval and military triumphal procession. This frieze was designed by Mr. Henning, junior, the son of Mr. Henning who was well known for his models of the Elgin marbles.
"The gates were manufactured by Messrs. Bramah. They are of iron, bronzed, and fixed or hung to the piers by rings of gun-metal. The design consists of a beautiful arrangement of the Greek honeysuckle ornament; the parts being well defined, and the raffles of the leaves brought out in a most extraordinary manner."
A rose garden, designed by Colvin & Moggeridge, was added in 1994.
Stanhope Lodge (Decimus Burton, 1824-25) at Stanhope Gate, demolished to widen Park Lane, was the home of Samuel Parkes who won the Victoria Cross in the Charge of the Light Brigade. Parkes was later Inspector of the Park Constables of the Park and died in the Lodge on 14 November 1864.
Hyde Park has been the venue for some famous rock concerts, including Pink Floyd (1968 and 1970), Jethro Tull (1968), Traffic (1968), Fleetwood Mac (1968), Blind Faith (1969), The Rolling Stones (1969), King Crimson (1969), Crosby, Stills & Nash (1969), Eric Burdon & War (1970), Canned Heat (1970), Grand Funk Railroad (1971), Roy Harper (1971), Wigwam (1975), Queen (1976), Pavarotti (1991), The Who (1996), Eric Clapton (1996), Michael Flatley (1998), Steps (2000), Bon Jovi (2003), Shania Twain (2003), Red Hot Chili Peppers (2004), Live 8 (2005), Queen + Paul Rodgers (2005), Daft Punk (2007), Depeche Mode (2006), Foo Fighters (2006), Aerosmith (2007), White Stripes (2007), and Capital 95.8 Party in the Park & Concert For Mandella 90 (2008). Red Hot Chili Peppers in 2004 did three concerts over the space of one week, these three concerts became the highest grossing concerts at a single venue in history. Eric Clapton performed here just recently during his 2008 Summer Tour, the concert took place on Saturday the 28th of June (the bill also featured Sheryl Crow & John Mayer performing Crossroads alongside Eric Clapton)
In Volume II of Alan Moore's graphic novel, The League of Extraordinary Gentlemen, Allan Quatermain implies that Hyde Park is named in honour of Mr. Edward Hyde, the bestial alter ego of Dr. Henry Jekyll, the titular character(s) of Robert Louis Stevenson's novella, The Strange Case of Dr. Jekyll and Mr. Hyde. This was a posthumous honour, done so to recognize Hyde's death while attempting to stop invaders from the planet Mars in their advance upon London (adapted from H. G. Wells' The War of the Worlds). In this story, Hyde Park was originally named "Serpentine Park".
In the Bernard Cornwell novel Sharpe's Regiment, a reenactment of the Battle of Vitoria was staged. During the reenactment, Major Richard Sharpe, led the Second Battalion of the South Essex Regiment into Hyde Park holding a French Imperial Eagle, which Sharpe had captured during the Battle of Talavera, to present his men to the Prince Regent in order to secure their protection from Sharpe's enemies.
Hyde Park is also the setting for Anne Perry's Victorian murder mystery, The Hyde Park Headsman in which several murder victims are found beheaded in or near the park under strange circumstances, causing near-hysterical terror in the residents of 1892 London. Superintendent Thomas Pitt is charged with discovering the murderer before he/she can strike again.
Hyde Park features as a setting in The Eye in the Door by British novelist Pat Barker. Chapter one in particular alludes to the Park's history as a gay cruising ground before the decriminalization of homosexuality in 1967.
The discovery of a young scientist's body in the Long Water, near the Peter Pan statue, is a central incident in Boris Starling's 2006 novel Visibility.
Also, In Destroy All Humans! 2, it is an area in Albion, a fictionalized London.
There are five London Underground stations located on or near the edges of Hyde Park and Kensington Gardens (which is contiguous with Hyde Park). In clockwise order starting from the south-east, they are:
Many buses also serve the local area.