Port Gibson is a city in Claiborne County, Mississippi, United States. The population was 1,567 at the 2010 census. Port Gibson is the county seat of Claiborne County, which is bordered on the west by the Mississippi River. It is the site of the Claiborne County Courthouse.
According to the United States Census Bureau, the city has a total area of 1.8 square miles (4.7 km), all land.
As of the census of 2000, there were 1,840 people, 692 households, and 447 families residing in the city. The population density was 1,048.0 people per square mile (403.7/km²). There were 787 housing units at an average density of 448.2 per square mile (172.6/km²). The racial makeup of the city was 19.40% White, 80.00% African American, 0.05% Native American, 0.22% Asian, 0.05% from other races, and 0.27% from two or more races. Hispanic or Latino of any race were 0.71% of the population.
There were 692 households out of which 30.6% had children under the age of 18 living with them, 31.9% were married couples living together, 27.2% had a female householder with no husband present, and 35.3% were non-families. 30.8% of all households were made up of individuals and 13.9% had someone living alone who was 65 years of age or older. The average household size was 2.64 and the average family size was 3.33.
In the city, the population was spread out with 29.3% under the age of 18, 10.5% from 18 to 24, 24.7% from 25 to 44, 20.9% from 45 to 64, and 14.5% who were 65 years of age or older. The median age was 34 years. For every 100 females, there were 80.2 males. For every 100 females age 18 and over, there were 76.2 males.
The median income for a household in the city was $24,848, and the median income for a family was $28,958. Males had a median income of $28,036 versus $21,115 for females. The per capita income for the city was $12,928. About 26.0% of families and 31.3% of the population were below the poverty line, including 41.9% of those under age 18 and 26.3% of those age 65 or over.