Lake of the Woods County was organized on November 28, 1922, when a vote by area residents separated the northern townships from Beltrami County. On January 1, 1923, the county officially began operations at its county seat in Baudette, Minnesota.
Before the advent of man around the Lake of the Woods, fire, water and ice worked to shape the land that today forms the county. Volcanic action and movements in the earth’s crust formed the first surface of this region. Erosion and volcanism worked alternately through time until a high, rocky chain of mountains was thrust up. The land that would be Lake of the Woods County was on the southwestern edge of this mountain range. Forces of erosion eventually wore the mountains down to their hard bases. Outcroppings of these rocks form the islands of the lake and appear occasionally jutting-out above the land area of the county. The rugged rock and lake terrain that remains today is known as the Canadian Shield, which ends in the Lake of the Woods. The rocks that form this shield are among the oldest on earth.
During the Ice Age, four major ice sheets covered northern Minnesota. When the glaciers withdrew, a lake formed between the height of the land to the south and the ice walls to the north. Known as Glacial Lake Agassiz, it submerged the county as well as part of the rest of Minnesota, North Dakota and a large portion of Canada. Eventually this lake shrank to leave the Lake of the Woods as a remnant body of water. The waters of the Lake of the Woods, like those of Lake Agassiz, flow north to empty into Hudson Bay.
A succession of beaches, sandy ridges, formed as the large lake shrank. One of the last of these was Campbell Beach, a sand ridge which is still noticeable as it runs across the county from north of Roosevelt to Pitt and south of Baudette.