2020 census As of the
2020 census, the county had 830,639 residents, which yielded a population density of 2,045.91 people per square mile (791.08/km2). The median age was 36.9 years, with 22.3% of residents under the age of 18 and 16.2% aged 65 or older; for every 100 females there were 93.6 males, and for every 100 females age 18 and over there were 90.9 males. There were 347,126 households in the county, of which 27.4% had children under the age of 18 living in them. Of all households, 37.9% were married-couple households, 21.7% were households with a male householder and no spouse or partner present, and 33.3% were households with a female householder and no spouse or partner present. About 34.6% of all households were made up of individuals and 11.8% had someone living alone who was 65 years of age or older. The county had 379,015 housing units, 8.4% of which were vacant; of the occupied units, 57.4% were owner-occupied and 42.6% were renter-occupied, and the homeowner and rental vacancy rates were 1.4% and 8.6%, respectively. 97.6% of residents lived in urban areas, while 2.4% lived in rural areas.
Racial and ethnic composition 2016–2020 American Community Survey According to the U.S. Census
American Community Survey, for the period 2016-2020 the estimated median annual income for a household in the county was $66,878, and the median income for a family was $92,480. About 15.3% of the population were living below the
poverty line, including 17.6% of those under age 18 and 10.8% of those age 65 or over. About 64.1% of the population were employed, and 41.8% had a bachelor's degree or higher.
2010 census As of the
2010 census, there were 802,374 people, 333,945 households, and 197,571 families living in the county. The population density was . There were 377,364 housing units at an average density of . The racial makeup of the county was 68.8% white, 25.7% black or African American, 2.0% Asian, 0.2% American Indian, 0.1% Pacific islander, 1.1% from other races, and 2.1% from two or more races. Those of Hispanic or Latino origin made up 2.6% of the population. Of the 333,945 households, 29.7% had children under the age of 18 living with them, 39.4% were married couples living together, 15.4% had a female householder with no husband present, 40.8% were non-families, and 33.9% of all households were made up of individuals. The average household size was 2.34 and the average family size was 3.04. The median age was 37.1 years.
2000 census As of the
2000 census, there were 845,303 people, 346,790 households, and 212,582 families living in the county. The population density was . There were 373,393 housing units at an average density of . The racial makeup of the county was 69.2%
White, 26.0% Black or African American, 0.1% Native American, 2.3% Asian, 0.01% Pacific Islander, 0.51% from other races, and 2.2% from two or more races. 2.8% of the population were
Hispanic or Latino of any race. There were 346,790 households, out of which 30.20% had children under the age of 18 living with them, 43.40% were
married couples living together, 14.30% had a female householder with no husband present, and 38.70% were non-families. 32.90% of all households were made up of individuals, and 10.60% had someone living alone who was 65 years of age or older. The average household size was 2.38 and the average family size was 3.07. In the county, the population was spread out, with 25.80% under the age of 18, 9.60% from 18 to 24, 29.70% from 25 to 44, 21.50% from 45 to 64, and 13.50% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 91.10 males. For every 100 females age 18 and over, there were 86.80 males. The median income for a household in the county was $40,964, and the median income for a family was $53,449. Males had a median income of $39,842 versus $28,550 for females. The
per capita income for the county was $24,053. About 8.80% of families and 11.80% of the population were below the
poverty line, including 16.20% of those under age 18 and 8.70% of those age 65 or over.
Population The county's highest population was recorded in the 1970 U.S. Census. Since then, the county has lost population at an average rate of three percent per decade. Although Hamilton County is experiencing a decline in birth rates and has higher death rates in older age groups (cohorts), out-migration of residents is the key factor in population loss. In the last decade, this population loss has been reversed, and it is estimated that both Hamilton County and the City of Cincinnati have grown their populations. The Cincinnati Metropolitan Statistical Area, over the last three decades has seen a 19 percent increase in population. Much of the region's growth has been through movement of Cincinnati and Hamilton County residents into neighboring counties. ==Government==