According to the U.S. Census Bureau, the county has a total area of, of which is land and is water. It is the fifth-largest county in Michigan by land area.
The 2010 United States Census indicates Delta County had population of 37,069. This decrease of 1,451 people from the 2000 United States Census represents a 3.8% population decrease during that 10-year period. In 2010 there were 15,992 households and 10,381 families in the county. The population density was 31.7 per square mile. There were 20,214 housing units at an average density of 17.3 per square mile. 94.7% of the population were White, 2.4% Native American, 0.4% Asian, 0.2% Black or African American, 0.2% of some other race and 2.1% of two or more races. 0.9% were Hispanic or Latino. 20.8% were of French, French Canadian or Cajun, 15.5% German, 10.3% Swedish and 7.6% Irish ancestry. There were 15,992 households out of which 25.5% had children under the age of 18 living with them, 51.7% were husband and wife families, 8.8% had a female householder with no husband present, 35.1% were non-families, and 29.8% were made up of individuals. The average household size was 2.28 and the average family size was 2.80. The county population contained 20.9% under age of 18, 7.3% from 18 to 24, 21.1% from 25 to 44, 31.6% from 45 to 64, and 19.1% who were 65 years of age or older. The median age was 46 years. 49.5% of the population were male, and 50.5% of the population female. The 2010 American Community Survey 3-year estimate indicates the median income for a household in the county was $40,967 and the median income for a family was $49,557. Males had a median income of $28,702 versus $15,093 for females. The per capita income for the county was $21,751. About 2.4% of families and 13.2% of the population were below the poverty line, including 17.4% of those under the age 18 and 8.5% of those age 65 or over.
Transportation
Major highways
– runs east-west through the lower part of the county. Enters from Schoolcraft County east of Garden Corners and runs west to intersection with US41 at Rapid River.
– runs north-south through central part of the county. Enters from Alger County at Trenary and runs south to Rapid River, then SW along Lake Michigan shore to SW corner of county.
– enters from Marquette County at NW corner of Delta County. Runs SE to intersection with US41 at Gladstone.
– runs east-west across SW tip of county. Enters from Menominee County at Schaffer and runs SE to intersection with US41 west of Narenta.
– runs from south tip of county at Sac Bay, NE to intersection with US2 at Garden Corners.
Airport
The county is served by Delta County Airport, southwest of Escanaba. It provides scheduled airline service to Detroit.
Government
Delta County was reliably Republican after the American Civil War, and until Franklin Roosevelt's New Deal. Since 1932, the Democratic Party nominee has carried the county vote in 15 of the 22 national presidential elections through 2016. Delta County operates the County jail, maintains rural roads, operates the major local courts, records deeds, mortgages, and vital records, administers public health regulations, and participates with the state in the provision of social services. The county board of commissioners controls the budget and has limited authority to make laws or ordinances. In Michigan, most local government functions – police and fire, building and zoning, tax assessment, street maintenance etc. – are the responsibility of individual cities and townships.
