The incident happened around 8 p.m. in the parking lot of Soaky Mountain Waterpark in Sevierville, about 25 miles southeast of Knoxville, WBIR-TV of Knoxville reported.
An argument apparently led to the gunfire, WATE-TV of Knoxville reported.
Both wounded women were transported to hospitals, the report said. Their medical conditions were not immediately known.
The three people detained for questioning included the alleged shooter, WBIR reported.
A spokesperson for the waterpark said officials there were fully cooperating with Sevierville police as an investigation continued.
This is a developing story. Check back for updates.