As of the 2010 United States Census,  269,291 people, 112,225 households, and 72,254 families resided in the county.
The population density was 237.5 inhabitants per square mile (91.7/km²).
The 185,992 housing units averaged 164.0 per square mile (63.3/km²).
The racial makeup of the county was 79.9% white, 13.4% black or African American, 1.0% Asian, 0.5% American Indian, 0.1% Pacific islander, 3.1% from other races, and 2.0% from two or more races.
Those of Hispanic or Latino origin made up 6.2% of the population.
In terms of ancestry, 15.3% were American, 13.4% were African American (which can include other ethnicities), 13.3% were Irish, 12.8% were German, 11.3% were English, and 6.1% were Italian.

Of the 112,225 households, 27.3% had children under the age of 18 living with them, 47.2% were married couples living together, 12.5% had a female householder with no husband present, 35.6% were not families, and 26.8% of all households were made up of individuals.
The average household size was 2.37 and the average family size was 2.84.
The median age was 41.1 years.

The median income for a household in the county was $43,142 and for a family was $51,608.
Males had a median income of $37,351 versus $29,525 for females.
The per capita income for the county was $24,811.
About 11.6% of families and 16.1% of the population were below the poverty line, including 25.2% of those under age 18 and 7.5% of those age 65 or over.
As of the 2010 United States Census,  269,291 people, 112,225 households, and 72,254 families resided in the county. The population density was 237.5 inhabitants per square mile (91.7/km²). The 185,992 housing units averaged 164.0 per square mile (63.3/km²). The racial makeup of the county was 79.9% white, 13.4% black or African American, 1.0% Asian, 0.5% American Indian, 0.1% Pacific islander, 3.1% from other races, and 2.0% from two or more races. Those of Hispanic or Latino origin made up 6.2% of the population. In terms of ancestry, 15.3% were American, 13.4% were African American (which can include other ethnicities), 13.3% were Irish, 12.8% were German, 11.3% were English, and 6.1% were Italian.
Of the 112,225 households, 27.3% had children under the age of 18 living with them, 47.2% were married couples living together, 12.5% had a female householder with no husband present, 35.6% were not families, and 26.8% of all households were made up of individuals. The average household size was 2.37 and the average family size was 2.84. The median age was 41.1 years.
The median income for a household in the county was $43,142 and for a family was $51,608. Males had a median income of $37,351 versus $29,525 for females. The per capita income for the county was $24,811. About 11.6% of families and 16.1% of the population were below the poverty line, including 25.2% of those under age 18 and 7.5% of those age 65 or over.
Horry County, South Carolina