The St Osyth Priory Estate is comprised of a unique range of heritage buildings, environmental and ecological features. The buildings alone comprise 22 separate Grade I, Grade II* and Grade II listed buildings and a number of Scheduled Ancient Monuments together with the registered park and garden.
The parkland is set adjacent to the River Colne Estuary Site of Special Scientific Interest which is an extensive wetland habitat of national and international importance for a wide range of wildfowl, invertebrates and salt marsh plant communities. It is also a County Wildlife Site containing a mosaic of historic ponds and avenues, woodland, reed bed and veteran trees combined with extensive wetland habitats which now provide complementary habitat for the birds and other wildlife using the estuarine marshes.
The St Osyth Priory Estate is of such significance as it has a social and cultural history dating back over 900 years with structures still in place from the monastic period and it is essential that it is preserved, restored and protected for the benefit of future generations.