It is 11.3 miles (18.2 km) south-east of Charing Cross, bordering the London Boroughs of Bromley and Greenwich.
The name is thought to be derived from Cetecopp meaning "seat-shaped or flat-topped hill"; it had its earliest recorded use in 1254.
According to Edward Hasted, "Thomas de Sedcopp was owner of this estate in the 35th year of king Henry VI.
They include Frognal House, the birthplace and residence of Thomas Townshend, 1st Viscount Sydney, converted for use as residential and nursing accommodation; Lamorbey House, now used by Rose Bruford College; Sidcup Place, a bar and restaurant; and The Hollies, converted for residential use.
Sidcup borders Blackfen to the north, Albany Park to the northeast and east, Foots Cray to the south-east, Chislehurst to the south and south-west, New Eltham to the west and Avery Hill to the north-west.
It retains many parks and open spaces hinting at the great estates and large homes which once stood in the area.
The town contains Queen Mary's Hospital, a large Leisure Centre, four colleges and three secondary schools.
[8] The building was demolished and Sidcup Health Centre, now known as the Barnard Medical Practice was erected in the site.
[8] Notable staff included: Queen Mary's Hospital was opened in 1917 with 300 beds in a number of wooden huts.
The club owns the Canada Heights motorcycle sport venue in Button Street, Swanley.
[19] The murder of teenager Rob Knox at the Metro Bar on Station Road in 2008 was national headline news.
Knox was an aspiring actor who had, just before his death, filmed a small part in Harry Potter and the Half-Blood Prince.
[24] These connect Sidcup with areas including Bexleyheath, Bromley, Catford, Crayford, Chislehurst, Dartford, Eltham, Greenwich, Erith, Lewisham, New Cross, Orpington, Swanley, Thamesmead, Welling & Woolwich.