As a human settlement, Dartford became established as a river crossing-point with the coming of the Romans; and as a focal point between two routes: that from west to east being part of the main route connecting London with the Continent; and the southerly route following the Darent valley. As a result, the town's main road pattern makes the shape of letter 'T'. The Dartford Marshes to the north and the proximity of Crayford in the London Borough of Bexley to the west, mean that the town's growth is to the south and east. Wilmington is contiguous with the town to the south; whilst the almost continuous Thames Gateway development means that there is little to show the town boundary in an easterly direction.