Penmon Park occupies the easternmost promontory of Anglesey, with the Priory occupying an enclave on the south side (NPRN 95543). It was enclosed by a roughly 4.0km high stone wall of which a 2.1km stretch cut off the promontory and the remainder ran parallel to the south shore and outlined the Priory enclave.
The park was divided into several large compartments, Penmon Park Deer Park to the east of the Priory and four 'parciau' or fields; Parc Pentir, Parc Dinmor, Parc-y-Ffynnon and Parc Trwyn-du. These are shown on the OS County series 1st edition of 1889 (Anglesey XV.2 & 6).
The byre associated with Priory House (NPRN 31077) opened into the deer park where the tenth century cross now in the church was originally situated (NPRN 57813).
It is possible that the park was a medieval creation, an adjunct of the Priory, although this earliest reference appears to be in 1708 (below). The park boundaries may be those of the Priory estate, adapted as a park following the reformation. There are traces of relict field boundaries and cultivation terraces throught the park (NPRN 302861), which presumably pre-date its enclosure.

Source: RCAHM Anglesey Inventory (1937), 129, 125 (map)

A keeper of Penmon Deer Park is commemorated in 1708. It remained stocked with deer, despite the occurrence of quarrying in park, until the First World War. Most of the park wall remained intact on the eve of the Second World War.

John Wiles 17.07.07