This poster presents findings and recommendations based on a process evaluation of an AY 2019-20 CAHSS scale up of major-based peer mentoring. The evaluation is based on field notes and interviews with peer mentors, students in participating departments, and Department leaders. Major-based peer mentors serve as campus/community resource bridges, a source of street knowledge on being a successful HSU student, and a conduit for major academic integration. PMs deliver support through office hours in the academic office, 1-to-1 appointments, and planned department events. This model is informed by: (1) research on cultural and social capital in higher education; (2) student success research on the unique needs for academic and career integration in the middle years; and (3) critical theories of student integration that center minoritized students in particular, and first-generation students more broadly, while supporting all students.