Ysbyty Mynydd Mawr is a community hospital located approx. 1.7 km north of Llannon, Carmarthenshire. The hospital was previously the County Isolation Hospital, denoted on the 1953 Ordnance County Series mapping (6", 4th edition). In 2012 the Board of Health Hywell Dda launched a consultation for the closure of Ysbyty Mynydd Mawr.

Development began on land to the east of the hospital for the care home Gwalia Mynydd Mawr.

Photographed during aerial reconnaissance by RCAHMW on 28th September 2011.
L. Osborne, 22nd March 2013.