As of the census of 2000, there were 306,067 people, 123,851 households, and 81,741 families residing in the county. The population density was 747 people per square mile (289/km²). There were 133,093 housing units at an average density of 325 per square mile (125/km²). The racial makeup of the county was 68.47% White, 25.61% Black or African American, 0.30% Native American, 1.04% Asian, 0.03% Pacific Islander, 3.25% from other races, and 1.30% from two or more races. 6.40% of the population were Hispanic or Latino of any race.
In 2005 62.9% of Forsyth county's population was non-Hispanic whites. 25.9% of the population was African-American. 9.5% was Latino. 1.3% was Asian and 1.1% reported two or more races. The decline in the last is due to changes in counting which basically excluded all Latinos from this category.
In 2000 there were 123,851 households out of which 30.50% had children under the age of 18 living with them, 48.90% were married couples living together, 13.50% had a female householder with no husband present, and 34.00% were non-families. 28.90% of all households were made up of individuals and 9.30% had someone living alone who was 65 years of age or older. The average household size was 2.39 and the average family size was 2.94.
In the county the population was spread out with 23.90% under the age of 18, 9.60% from 18 to 24, 31.10% from 25 to 44, 22.80% from 45 to 64, and 12.60% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 91.50 males. For every 100 females age 18 and over, there were 87.40 males.
The median income for a household in the county was $42,097, and the median income for a family was $52,032. Males had a median income of $36,158 versus $27,319 for females. The per capita income for the county was $23,023. About 7.90% of families and 11.00% of the population were below the poverty line, including 15.10% of those under age 18 and 9.70% of those age 65 or over.