Tennessee Bureau of Investigation spokeswoman Susan Niland said the shooting in Brownsville occurred before midnight Friday when a fight broke out at the armory.
Authorities believe the facility had been rented out for a party.
Niland said the victims, including two juveniles and eight adults, were transported to Jackson General Hospital.
Two are expected to be transported to The Med in Memphis with non-life threatening injuries.
Niland said seven others were treated for injuries and have been released, or are in the process of being released. The scene at the armory has been cleared.