Baffin Island is the largest island in the Arctic Archipelago, measuring 305,000 km2. The island was first discovered by Europeans in 1576 and was used extensively in the whaling industry in the 19th and 20th centuries. Baffin Bay and Davis Strait, to the east, are often open during the summer, but the western side is typically closed by ice year-round. The topography of the island is highly varied, ranging from the most rugged mountains to the flattest lowlands of the Canadian Arctic. Raised Canadian Shield forms mountain ranges along the east coast, while the relief slopes downwards to the west to form a flat-bedded Paleozoic sedimentary basin.
The Arctic Cordillera runs along the eastern coast of Baffin Island. Alpine mountains dominate the range with sharp peaks and ridges, though some flat-topped mountains are present. The Penny and Barnes ice caps are the largest ice caps on the island and have smoothly rolling terrain with no breaks in their coverage. North of the Penny ice cap, the mountain range becomes lower and narrower, disappears into Pond Inlet, and then reappears on Bylot Island. Lying off the northeastern coast of Baffin Island, Bylot Island is almost completely covered in an ice cap, which is pierced by mountain peaks and ridges.
Hall Peninsula and the promontory west of Frobisher Bay are lowlands of Precambrian gneiss rock. The terrain is rough and rocky, with hills near the coast. Both peninsulas have permanent ice; the Grinnel glacier on Hall Peninsula calves icebergs into Frobisher Bay.
Brodeur and Borden Peninsulas form a plateau in the northwest. Brodeur Peninsula has a flat-topped terrain that is cut by deep river valleys and a coast lined with sheer cliffs. Similarly, Borden Peninsula is composed of flat, dissected rock in the north, but wide river valleys divide the scarps and flat-topped hills that occupy the south.
The area between the two northern peninsulas and Foxe Peninsula is lowland formed by the Canadian Shield. The lake-studded coastal strip is a smooth and featureless plateau that rises gradually in elevation from the west coast to the eastern mountains. The Great Plain of the Koukdjouak, between Lake Nettiling and Foxe Basin, is broad grassland. South of the plain, a strip of coastal grassland has grown on old beaches and rises to an elevated plain. This coastal strip is littered with shallow ponds that are fed by runoff streams. Even farther south, the Putnam Highlands form a flat, north-facing scarp.
Foxe Peninsula juts out the southwestern corner of Baffin Island. The southern half is high, rough, and very rocky, but becomes increasingly low, drift-covered, and dotted with rocky outcroppings towards the northern half.
Nunavut's capital, Iqaluit formerly known as Frobisher Bay is located on Baffin Island and is home to 5236 people. Other communities include: