This paper highlights Kanien'kéha (Mohawk language) "adult immersion" as an effective and expedient program structure for creating second-language (L2) speakers and argues that concentrated efforts to strengthen and expand adult immersion are essential in advancing Kanien'kéha revitalization. By conducting a comprehensive vitality assessment, detailing the 'health' of Kanien'kéha use and transmission in all Kanien'kehá:ka (Mohawk) communities, this paper argues that adult L2 speakers play a crucial role in revitalization and that adult immersion is essential in creating those adult speakers. Adult immersion as a unique program structure is defined and the foundational components of an effective adult immersion program are described, as well as the challenges that these programs continue to face.