The county's name is claimed to be a corruption of the French term "Michilimackinac," which referred to the straits area as well as the French settlement at the tip of the lower peninsula. See and compare, List of Michigan county name etymologies, List of Michigan counties, and List of abolished U.S. counties.
As of the census of 2000, there were 11,943 people, 5,067 households, and 3,410 families residing in the county. The population density was 12 persons per square mile (5/km²). There were 9,413 housing units at an average density of 9/sq mi (4/km²). The racial makeup of the county was 80.07% White, 0.20% Black or African American, 14.21% Native American, 0.31% Asian, 0.02% Pacific Islander, 0.28% from other races, and 4.92% from two or more races. 0.90% of the population were Hispanic or Latino of any race. 18.7% were of German, 9.4% English, 8.1% Irish, 7.3% French, 6.0% American and 6.0% Polish ancestry according to Census 2000. 97.6% spoke English as their first language.
There were 5,067 households out of which 26.50% had children under the age of 18 living with them, 55.60% were married couples living together, 8.10% had a female householder with no husband present, and 32.70% were non-families. 28.00% of all households were made up of individuals and 11.90% had someone living alone who was 65 years of age or older. The average household size was 2.32 and the average family size was 2.81.
In the county the population was spread out with 22.20% under the age of 18, 6.00% from 18 to 24, 25.10% from 25 to 44, 28.40% from 45 to 64, and 18.20% who were 65 years of age or older. The median age was 43 years. For every 100 females there were 99.70 males. For every 100 females age 18 and over, there were 97.20 males.
The median income for a household in the county was $33,356, and the median income for a family was $39,929. Males had a median income of $30,805 versus $22,753 for females. The per capita income for the county was $17,777. About 7.20% of families and 10.50% of the population were below the poverty line, including 13.70% of those under age 18 and 8.40% of those age 65 or over.