Aldenham is a village and civil parish in the borough of Hertsmere in Hertfordshire, England. The parish includes Radlett and Letchmore Heath as well as Aldenham village itself. The village of Aldenham lies 3.5 miles (5.6 km) north-east of Watford and 2 miles (3.2 km) southwest of Radlett. Aldenham was mentioned in the Domesday Book and is one of Hertsmere's 14 conservation areas. The village has eight pre-19th-century listed buildings and the parish itself is largely unchanged, though buildings have been rebuilt, since Saxon times when the majority of the land was owned by the abbots of Westminster Abbey.

Hertsmere is a local government district with borough status in Hertfordshire, England. Its council is based in Borehamwood. Other settlements in the borough include Bushey, Elstree, Radlett and Potters Bar. The borough contains several film studios, including Elstree Studios and the BBC Elstree Centre at Borehamwood. The borough borders Three Rivers, Watford, St Albans, and Welwyn Hatfield in Hertfordshire and the three north London boroughs of Harrow, Barnet and Enfield. Hertsmere is located mainly within the M25 Motorway.