Sheerness (14), a fortified seaport and important garrison town with important naval dockyards in Kent, occupying the NW. corner of Sheppey Isle, where the Medway joins the Thames, 52 m. E. of London; is divided into Blue-town (within the garrison, and enclosing the 60 acres of docks), Mile-town, Banks-town, and Marina-town (noted for sea-bathing).