St Tysilio's Church, is located on Church Island, also known as Llandysilio Island, is a small island in the Menai Strait, on the shores of Anglesey.
Church Island is located in the Menai Strait, off the south-eastern shore of the island of Anglesey, close to the town of Menai Bridge. It is located in a stretch of the Menai known as the Swellies, with the stretch of water to the south of the church is prone to dangerous tidal currents. Access to the island is via a short tidal causeway, which meets the Wales Coast Path long-distance footpath at its Anglesey end.
The first recorded occupation of the island was by Prince Tysilio, the son of Brochwel Ysgithrog, king of Powys, who then become Saint Tysilio. Tysilio arrived on Church Island in about 630 and founded a hermitage and remained for around seven years, before moving to Meifod where he became an abbot. No trace of Tysilio's hermitage survives on Church Island today.
The church of Saint Tysilio was founded in the fifteenth century although it is not known who built the church, but it is likely that it replaced an earlier structure on the same site. The church is a single-chamber church, along with its graveyard and a war memorial near the highest point, which was designed by Harold Hughes and was given a grade II listing in 1997.
Birds found close to the island include oystercatchers, curlews, common terns, and in recent times, little egrets. There are also a number of primroses growing, which give the island a golden appearance during the spring months.