Hello my step son was convicted of statutory rape in South Dakota, but now has moved to Tennessee. So I am trying to find out if statutory rape is a felony?

In Tennessee, Statutory Rape is a felony Class E or D.

In South Dakota, these violations can be felony or misdemeanor depending on the law that was violated and the circumstances of the violation. South Dakota does not have a law titled "Statutory Rape" but has the equivalent laws under different names. There is no way for us to determine what he may have been charged for without more details.