A mound building race of uknown origin inhabited present day Kanabec County in pre-historic times. Some of these mounds can be found at Fish Lake and Knife Lake and near the outlet of the Ann River. Sioux Indians lived here at the time of Radisson's visit in 1660, possibly the first white men in the area. The Chippewa Indians moved westward into this area to escape the masses of white settlers moving west from the eastern seaboard. This area was the scene of many bloody battles between the Chippewa and the Sioux Indians. One story of how the county got its name is that the Chippewa called the winding river (which runs from north to south) Kan-a-bec [Ojibwe: "ginebig"], which means "snake."

Extensive lumber operations along the Ann and Snake Rivers provided for early industrial growth in the county. The first lumber operation began in 1838 at Millet Rapids. Brunswick was the site of the first lumber operation and the first post office. Kanabec County was established in 1858 by the newly found state legislature. Brunswick became the first county seat in 1860. Swedish immigrants began settling in the area around Brunswick in 1870. The St. Cloud to Hinckley railroad track was finished through the towns of Ogilvie, Mora and Quamba in 1882. The last passenger train left Mora in 1951.

Logging operations began a drastic slowdown around the turn of the century. The cleared land began to be put into farming at this time. Hay was the first important crop. Potatoes became popular later, but disease developed and potatoes have not been an important crop in the county since that time. Present day principle crops include hay, corn and oats. 39,900 acres of all types of hay were harvested in Kanabec County with an average yield of 2 tons per acre in 1974, a very dry year. Alfalfa and alfalfa mixtures averaged 2.4 tons per acre off of 19,400 acres in 1974. Corn yields average 43.4 bushels per acre in 1974 although the average yield in 1973 was 75 bushels per acre off of 17,000 acres. Oat yields averaged 44.1 bushells on 9,600 acres [text missing] on 202 acres.