34 U.S.C. § 20918

A sex offender shall appear in person, allow the jurisdiction to take a current photograph, and verify the information in each registry in which that offender is required to be registered not less frequently than— (1) each year, if the offender is a tier I sex offender; (2) every 6 months, if the offender is a tier II sex offender; and (3) every 3 months, if the offender is a tier III sex offender.