royal park in the borough of Westminster (Westminster, City of), London. Located north of Buckingham Palace, east of Hyde Park, and west of the neighbourhood of St. James (Saint James), it covers about 53 acres (21 hectares) of land.

The park was enclosed in the 16th century, and it was later designated a royal park by Charles II (reigned 1660–85). In the 18th century it was an isolated location that often concealed highwaymen and served as the meeting place for duels, but it was also used for fireworks displays and balloon ascents. Green Park is the least stylized and ornamented of London's royal parks.