Big Sandy is a town in Benton County, Tennessee, United States. The population was 557 at the 2010 census.
Big Sandy is located at 36°14′3″N 88°5′9″W (36.234203, -88.085869).
According to the United States Census Bureau, the town has a total area of 0.7 square miles (1.8 km2), all land.
Big Sandy is concentrated around the intersection of State Route 69A and State Route 147.
As of the census of 2000, there were 518 people, 241 households, and 145 families residing in the town. The population density was 728.0 people per square mile (281.7/km2). There were 298 housing units at an average density of 418.8 per square mile (162.1/km2). The racial makeup of the town was 99.23% White, 0.19% from other races, and 0.58% from two or more races. Hispanic or Latino of any race were 0.19% of the population.
There were 241 households, out of which 22.0% had children under the age of 18 living with them, 44.4% were married couples living together, 11.6% had a female householder with no husband present, and 39.8% were non-families. 36.9% of all households were made up of individuals, and 19.1% had someone living alone who was 65 years of age or older.