According to the U.S. Census Bureau, the county has a total area of, of which is land and is water. It is the fourth-smallest county in Ohio by total area. The county is drained by the Sandusky and Olentangy Rivers.
As of the census of 2000, there were 46,966 people, 18,957 households, and 13,175 families living in the county. The population density was 117 people per square mile. There were 20,178 housing units at an average density of 50 per square mile. The racial makeup of the county was 97.99% White, 0.59% Black or African American, 0.20% Native American, 0.31% Asian, 0.02% Pacific Islander, 0.24% from other races, and 0.65% from two or more races. 0.77% of the population were Hispanic or Latino of any race. 40.4% were of German, 21.4% American, 8.1% English and 7.8% Irish ancestry according to Census 2000. There were 18,957 households out of which 31.20% had children under the age of 18 living with them, 55.10% were married couplesliving together, and 30.50% were non-families. 26.30% of all households were made up of individuals and 11.50% had someone living alone who was 65 years of age or older. The average household size was 2.45 and the average family size was 2.94. In the county, the population was spread out with 24.90% under the age of 18, 8.00% from 18 to 24, 27.60% from 25 to 44, 24.30% from 45 to 64, and 15.20% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 93.40 males. For every 100 females age 18 and over, there were 90.80 males. The median income for a household in the county was $36,227, and the median income for a family was $43,169. Males had a median income of $33,319 versus $21,346 for females. The per capita income for the county was $17,466. About 7.80% of families and 10.40% of the population were below the poverty line, including 13.70% of those under age 18 and 7.50% of those age 65 or over. According to the United States Census Bureau, women make up about 51.3% of the population, as of 2014.
2010 census
As of the 2010 United States Census, there were 43,784 people, 18,099 households, and 12,108 families living in the county. The population density was. There were 20,167 housing units at an average density of. The racial makeup of the county was 97.2% white, 0.9% black or African American, 0.4% Asian, 0.1% American Indian, 0.3% from other races, and 1.1% from two or more races. Those of Hispanic or Latino origin made up 1.2% of the population. In terms of ancestry, 43.3% were German, 14.3% were Irish, 13.7% were American, and 11.0% were English. Of the 18,099 households, 29.9% had children under the age of 18 living with them, 50.6% were married couples living together, 11.5% had a female householder with no husband present, 33.1% were non-families, and 28.4% of all households were made up of individuals. The average household size was 2.39 and the average family size was 2.89. The median age was 41.9 years. The median income for a household in the county was $41,228 and the median income for a family was $49,647. Males had a median income of $40,304 versus $28,118 for females. The per capita income for the county was $20,590. About 10.8% of families and 13.0% of the population were below the poverty line, including 21.3% of those under age 18 and 6.2% of those age 65 or over.
Politics
Prior to 1924, Crawford County was a strongly Democratic county. Since 1924, it has become strongly Republican, only backing Democratic candidates three times since then.
