Harrison County is part of the Gulfport–Biloxi, Mississippi Metropolitan Statistical Area.
As of the census of 2000, there were 189,601 people, 71,538 households, and 48,574 families residing in the county. The population density was 326 people per square mile (126/km²). There were 79,636 housing units at an average density of 137 per square mile (53/km²). The racial makeup of the county was 73.15% White, 21.09% Black or African American, 0.45% Native American, 2.60% Asian, 0.09% Pacific Islander, 0.90% from other races, and 1.72% from two or more races. 2.59% of the population were Hispanic or Latino of any race.
There were 71,538 households out of which 33.50% had children under the age of 18 living with them, 48.10% were married couples living together, 15.10% had a female householder with no husband present, and 32.10% were non-families. 25.80% of all households were made up of individuals and 8.30% had someone living alone who was 65 years of age or older. The average household size is 2.55 and the average family size is 3.07.
In the county the population was spread out with 26.00% under the age of 18, 11.10% from 18 to 24, 30.50% from 25 to 44, 21.20% from 45 to 64, and 11.10% who are 65 years of age or older. The median age was 34 years. For every 100 females there were 99.10 males. For every 100 females age 18 and over, there were 97.50 males.
The median income for a household in the county was $35,624, and the median income for a family was $41,445. Males had a median income of $29,867 versus $22,030 for females. The per capita income for the county was $18,024. 14.60% of the population and 11.60% of families were below the poverty line. Out of the total population, 20.70% of those under the age of 18 and 11.30% of those 65 and older were living below the poverty line.
Harrison County has the sixth highest per capita income in the State of Mississippi.