As of the census of 2000, there were 5,876 people, 2,478 households, and 1,536 families residing in the city. The population density was 1,708.9 people per square mile (659.5/km²). There were 2,768 housing units at an average density of 805.0 per square mile (310.7/km²). The racial makeup of the city was 89.09% White, 8.73% African American, 0.22% Native American, 0.19% Asian, 0.75% from other races, and 1.02% from two or more races. Hispanic or Latino of any race were 1.68% of the population.
There were 2,478 households out of which 28.9% had children under the age of 18 living with them, 44.8% were married couples living together, 14.2% had a female householder with no husband present, and 38.0% were non-families. 33.3% of all households were made up of individuals and 17.4% had someone living alone who was 65 years of age or older. The average household size was 2.28 and the average family size was 2.89.
In the city the population was spread out with 22.7% under the age of 18, 10.6% from 18 to 24, 28.4% from 25 to 44, 21.0% from 45 to 64, and 17.4% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 86.0 males. For every 100 females age 18 and over, there were 83.1 males.
The median income for a household in the city was $27,050, and the median income for a family was $34,074. Males had a median income of $30,584 versus $21,081 for females. The per capita income for the city was $17,585. About 17.1% of families and 19.4% of the population were below the poverty line, including 29.4% of those under age 18 and 17.8% of those age 65 or over.
The Mt. Sterling–Montgomery County Library was established in 1871. The Mt. Sterling–Montgomery County Library moved to the current location, accessible from both Main and Locust Streets, in July 1984. The building was officially dedicated on September 30, 1984. The local library added a branch in Camargo in October, 2008.