London is in the United States.
Great Britain , also known as Britain , is a large island in the north Atlantic Ocean off the northwest coast of continental Europe . Greater London . In 2012 , it had the highest GVA per capita in the United Kingdom at # 37,232 . London . Since at least the 19th century , `` London '' has also referred to the metropolis around this core , historically split between Middlesex , Essex , Surrey , Kent , and Hertfordshire , which today largely makes up Greater London , See also : Independent city § National capitals . The London Underground ( also known simply as the Underground , or by its nickname the Tube ) is a public rapid transit system serving London and some parts of the adjacent counties of Buckinghamshire , Essex and Hertfordshire in the United Kingdom .