Named after the Island in Atlantic Ocean (15th Century maps) on verge of the unknown, near Antilla and St. Brandan.
A insula is an island (islands), an isolated land area (or group of such areas) surrounded by, or nearly surrounded by, a liquid area (sea or lake). On Titan they are named after islands from legends and myths.
Image Source. Marker locations are approximate and may not always appear to align with image on map.