Seal Island (also known as Great Seal Island) is an island on the outermost extreme of Southwestern Nova Scotia, Canada, and is the second southernmost point of land of Nova Scotia. The southern tip of nearby Cape Sable is 250 m farther south than the southern tip of Seal Island. It is located in Municipalité Argyle Municipality in Yarmouth County. It is approximately 2.7 miles long and 0.5 miles wide. It is the biggest of a group of five islands which extend north for 7.5 miles.