The East Midlands is one of nine official regions of England at the first level of NUTS for statistical purposes. It consists of Derbyshire, Leicestershire, Lincolnshire (except North and North East Lincolnshire), Northamptonshire, Nottinghamshire and Rutland. The region has an area of 15,627 km2 (6,034 sq mi), with a population over 4.5 million in 2011. There are five main urban centres, Derby, Leicester, Lincoln, Northampton and Nottingham. Others include Boston, Skegness, Chesterfield, Corby, Grantham, Hinckley, Kettering, Loughborough, Mansfield, Newark-on-Trent and Wellingborough. Relative proximity to London and its position on the national motorway and trunk road networks help the East Midlands to thrive as an economic hub. East Midlands Airport, 18 miles (29 km) from Leicester, is between Derby, Loughborough and Nottingham.