Llancillo is a civil parish located in south-west Herefordshire, England. It is situated approximately 13 miles (20 km) south-west of Hereford, the city and county town. The parish borders Wales to the south, with the nearest Welsh town being Abergavenny, located about 7 miles (11 km) to the south-southwest.
The area is home to the isolated Church of St Peter, which is a Grade II* listed building dating back to the 11th century.