 Mail for this area is sorted at the Home Counties North Mail Centre in Hemel Hempstead, having been sorted at the Watford Mail Centre until its closure in 2011.The area covered includes all of the borough of Watford, most of the Three Rivers district, the western part of the Hertsmere district and small parts of the Dacorum and St Albans districts.WD3 also covers the village of Chenies in the Chiltern district of Buckinghamshire, plus a small protrusion of Harefield in the London Borough of Hillingdon.