These textile mills are now closed. With the construction of Lake Hartwell in 1963, Lake Keowee in 1971, and Lake Jocassee in 1974, Seneca and the area saw dramatic changes. The Oconee Nuclear Station was built on Lake Keowee. The recreation provided by the lakes and other attractions such as nearby Clemson University brought many retirees from other parts of the country. Retirement communities have been built in the area. Early on April 13th, 2020, a high-end EF3 tornado struck residential areas of south and east of Seneca. Many buildings were damaged or destroyed and one person were killed. In and around Seneca, there are a number of historic buildings and districts that are on the National Register of Historic Places:   Seneca is located at (34.684145, -82.955778). According to the United States Census Bureau, the city has a total area of , of which is land and (0.56%) is water. As of the census of 2000, there were 7,652 people, 3,286 households, and 2,096 families residing in the city. The population density was 1,084.6 people per square mile (418.5/km²). There were 3,677 housing units at an average density of 521.2 per square mile (201.1/km²). The racial makeup of the city was 63.32% White, 33.77% African American, 0.31% Native American, 0.63% Asian, 0.01% Pacific Islander, 0.65% from other races, and 1.31% from two or more races. Hispanic or Latino of any race were 1.53% of the population. There were 3,286 households out of which 27.4% had children under the age of 18 living with them, 42.2% were married couples living together, 17.5% had a female householder with no husband present, and 36.2% were non-families. Of all households 32.3% were made up of individuals and 13.2% had someone living alone who was 65 years of age or older. The average household size was 2.32 and the average family size was 2.93. In the city, the population was spread out with 24.4% under the age of 18, 9.5% from 18 to 24, 25.3% from 25 to 44, 24.7% from 45 to 64, and 16.0% who were 65 years of age or older.