Oklahoma County was originally called County Two and was one of seven counties established by the Organic Act of 1890.
County business initially took place in a building at the intersection of California Avenue and Robinson Street until the construction of the first Oklahoma County Courthouse at 520 West Main Street in the 1900s. In 1937, the county government was moved to a building at 321 Park Avenue, which now serves only as the county courthouse.
There were 277,615 households out of which 28.5% had children under the age of 18 living with them, 43.1% were married couples living together, 15.4% had a female householder with no husband present, and 37.8% were non-families. 31.9% of all households were made up of individuals and 9.7% had someone living alone who was 65 years of age or older. The average household size was 2.56 and the average family size was 3.26.
In the county, the population was spread out with 25.60% under the age of 18, 10.90% from 18 to 24, 30.00% from 25 to 44, 21.40% from 45 to 64, and 12.20% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 94.20 males. For every 100 females age 18 and over, there were 90.80 males.
The median income for a household in the county was $42,916, and the median income for a family was $54,721. The per capita income for the county was $25,723. About 11.70% of families and 15.30% of the population were below the poverty line, including 21.70% of those under age 18 and 8.60% of those age 65 or over.
Voter Registration and Party Enrollment as of January 15, 2012