St Fillan's Kirk, Seat and Well are located in the hamlet of Kilallan, once the main religious centre of the ancient parish of Kilallan or Killellan, close to Kilmacolm, Renfrewshire, Scotland. The old parish was united with Houston in 1760 although the church saw occasional use until 1771. The ruins of the kirk are a scheduled monument and the surrounding graveyard is a Listed Building. The ruins stand some 4 miles (6 km) west of the centre of Houston, just off the Kilallan Road.

Renfrewshire is one of the 32 council areas of Scotland.