Grimsby is a traditional fishing port in Lincolnshire, one of the eastern counties of England. It is situated at the mouth of the River Humber. It is physically linked to the adjoining town of Cleethorpes, with which it makes up the unitary authority of North East Lincolnshire. It is home to Britain’s largest port complex in terms of tonnage, and a large number of industries along the humber provide a lot of the town's employment. The main route in is via the A46 (Lincoln, Newark) or from the M180, which turns into the A180 in neighbouring North Lincolnshire, and links Grimsby with main routes to Hull and the Midlands. Humberside airport is an extremely short drive away and has scheduled flights to Aberdeen and Amsterdam, as well as charter flights to other european cities. There are frequent train services between Cleethorpes and Manchester which call at Grimsby Town station. A bus service links Grimsby to Hull (X1), Lincoln (3A) and Louth (51), operated by stagecoach. National Express also operates a service through Grimsby although only once or twice a day.