English: habitational name from the city in Kent, which is recorded by Bede ( c.730 ) under the names of both Dorubrevi and Hrofæcæstre. The former represents the original British name, composed of the elements duro- ‘fortress’ and brīvā‘bridge’. The second represents a contracted form of this (possibly affected by folk etymological connection with Old English hrōf ‘roof’) combined with an explanatory Old English cæster ‘Roman fort’ (from Latin castra ‘military camp’). There is a much smaller place in Northumbria also called Rochester, which seems to have been named in imitation of the more important one, but which is a more than occasional source of the surname. In other cases there may also have been confusion with Wroxeter in Shropshire, recorded in Domesday Book as Rochecestre.
Dictionary of American Family Names © Patrick Hanks 2003, 2006.