According to DOJ, tribal nations are disproportionately affected by violent crimes and sex offenses in particular. In 2006, Congress passed SORNA, which introduced new sex offender registration and notification standards for states, territories, and eligible tribes. The act made special provisions for eligible tribes to elect either to act as registration jurisdictions or to delegate SORNA functions to the states in which they are located. This book addresses, among other things, the extent to which eligible tribes have retained their authority to implement, and for those that did, describe their implementation status; and implementation challenges tribes that retained their authority reported, and steps federal agencies have taken or could take to address these challenges.