The Lincolnshire Coast and Marshes is the most easterly NCA in Greater Lincolnshire. It borders the North Sea and the Lincolnshire Wolds and extends from Barton upon Humber in the north to the mouth of the Humber Estuary in the northeast and to Skegness in the south. The NCA contains a chalk aquifer that provides an important water source for the region. The NCA can be divided into three distinct areas: 

The Middlemarsh, which runs parallel to the Lincolnshire Wolds NCA, and contains a comparatively substantial area of woodland for the NCA, including ancient woodlands and hedgerows. 

The Outmarsh, which was historically an area of grassland, however, following the implementation of effective drainage and sea banks, has become an increasingly arable area.

The Coast, which is a highly dynamic landscape subject to erosion and accretion. Large areas of the Coast are undeveloped and managed as nature reserves, including the internationally significant Lincolnshire Coronation Coast and Gibraltar Point National Nature Reserves.

The NCA contains several important rivers, including the Great Eau, Freshney and the Steeping. The NCA is also known for its blow wells which can be habitats for the elusive crystal moss animal.

To the north of the NCA, Grimsby and Immingham provide important trade links to Europe, and the Coast supports important infrastructure with offshore wind energy and the wider energy network.