Cassiobury House was a country house in Cassiobury Park, Watford, England. It was notable for being the ancestral seat of the Earls of Essex. Originally a Tudor building, dating from 1546 for Sir Richard Morrison, it was substantially remodelled in the 17th and 19th centuries and ultimately demolished in 1927. The surrounding Cassiobury Park was turned into the main public open space for Watford.
St Albans Abbey claimed rights to the manor of Cashio (then called "Albanestou"), which included Watford, dating from a grant by King Offa in AD 793. When Henry VIII dissolved the monasteries in 1539, Watford was divided from Cashio, and Henry made himself lord of the manor of Cassiobury. In 1546 he granted the manor to Sir Richard Morrison, who started to build Cassiobury House in the extensive gardens, but had not made much progress by 1553 when he went into exile abroad. The estate grounds were much larger than they are today, reaching as far as North Watford and southwards almost to Moor Park. After the death of his father in 1556, Sir Charles Morrison (1549-1599) continued building and completed the mansion, which had 56 rooms, a long gallery, stables, a dairy and a brewhouse. Sir Charles was succeeded by his son, also called Charles Morrison (1587-1628); the younger Charles had a daughter, Elizabeth Morrison (1610-1660).
Coordinates: 51°39′36″N 0°24′04″W / 51.66°N 0.401°W / 51.66; -0.401
The Cassiobury Estate is a suburban residential area of Watford in Hertfordshire, England. It is bounded to the south by Cassiobury Park, the main public park in the town, to the west by playing fields next to the River Gade, and to the northeast by Hempstead Road. It is mostly characterised by 1930s Mock Tudor houses.
To the northwest of Cassiobury, outside the Borough of Watford in the Three Rivers District, is The Grove, the former estate and house of the Earls of Clarendon. This has been converted into a luxury hotel and with extensive grounds.
The area is currently served by a London Underground station, Watford tube station, the terminus of the Metropolitan line's Watford branch. This station is due to close in 2016 when the line is diverted to terminate at Watford Junction as part of the Croxley Rail Link project; after this, the Cassiobury will be served by the new Cassiobridge tube station instead, approximately 870 metres (0.54 mi) south of the current station.