Apsley was a 19th-century mill village in the county of Hertfordshire, England. It is a historic industrial site situated in a valley of the Chiltern Hills. It is positioned below the confluence of two permanent rivers, the Gade and Bulbourne. In an area of little surface water this was an obvious site for the location of water mills serving local agriculture and from the early 19th century became an important centre for papermaking. Today it is a suburb of the larger town of Hemel Hempstead.