Prince Charles Island, Nunavut, 9521 km2, 130 km long and 100 km wide, is the largest island in Foxe Basin. Lying west of Baffin Island, it is an outcrop of a coast of postglacial marine deposition, and exhibits the characteristics of this kind of topography, having monotonously straight, flat coasts with a shallow offshore zone. The shore consists of wide mud flats, littered with boulders and crossed by occasional watercourses, and passes imperceptibly to the inland tundra marshes. The maximum elevation is only 73 m; local relief is generally in the order of 10 m or less.

Over one and a half times larger than Prince Edward Island, the island was only discovered and mapped in 1948 by a Royal Canadian Air Force aerial survey. In 1932 there was a report of land in the area of Prince Charles Island but the information was never mapped and its true extent was not known. The island was named in honour of Prince Charles, who was born the same year the island was discovered.