Collinsville is an unincorporated community and census-designated place (CDP) in Lauderdale County, Mississippi, United States. The population was 1,948 at the 2010 census.
Collinsville is located in northwestern Lauderdale County at 32°29′16″N 88°50′39″W (32.487906, -88.844205). Mississippi Highway 19 passes through the community, leading southeast 13 miles (21 km) to Meridian, the county seat, and northwest 26 miles (42 km) to Philadelphia.
According to the United States Census Bureau, the CDP has a total area of 14.3 square miles (37.0 km2), of which 0.03 square miles (0.07 km2), or 0.18%, are water. The town and Highway 19 lie on a low ridge separating Suqualena Creek to the west and Twitley Branch to the east, both of which are tributaries of Okatibbee Creek and part of the Chickasawhay/Pascagoula River watershed. Okatibbee Dam, forming 5.9-square-mile (15 km2) Okatibbee Lake, is at the eastern edge of the Collinsville CDP.
As of the census of 2000, there were 1,823 people, 701 households, and 541 families residing in the CDP. The population density was 115.7 people per square mile (44.7/km2). There were 739 housing units at an average density of 46.9/sq mi (18.1/km2). The racial makeup of the CDP was 86.56% White, 12.51% African American, 0.38% Asian, and 0.55% from two or more races. Hispanic or Latino of any race were 1.32% of the population.
There were 701 households, out of which 39.2% had children under the age of 18 living with them, 63.9% were married couples living together, 10.3% had a female householder with no husband present, and 22.8% were non-families.