This Research Experience for Undergraduates (REU) site at the University of Arizona (UA) will provide summer research experience opportunities to geoscience students from two-year community and tribal colleges around the southwest. The goal of the program is to stimulate interest in the geosciences early in the academic careers of these students and create a clear and inviting pathway to transfer into four-year college geoscience programs for these students. This REU program will also provide post-research project mentoring conducive to retaining the students through completion of their four-year degree. The project is intended to create a lasting network of collaboration between the University of Arizona and partner two-year colleges in the region that will ultimately facilitate stronger transfer pathways for all two-year college students. The results of this program can also serve as a model for historically excluded group-focused research experiences for undergraduates for other STEM disciplines. This REU program will work to address the ongoing challenge of limited enrollment and retention among historically excluded groups from the geosciences through a program specifically targeting student recruitment from ~15 predominantly Hispanic/Latinx, Black, and Native American-serving regional community and tribal colleges from around the southwestern US. An initial 2-week campus immersion for all participants, introducing them to the breath of geosciences academic and career opportunities, campus life and the university educational setting, will be followed by a ~5-week mentored research project, working either at the UA in the lab, in a field-based setting, or in a co-mentored setting from their home base with community college and tribal college co-mentors. During the final week of the program all students will return to the UA for summative activities, including formal research presentations of their work, and allowing for family participation in recognition of their student?s achievements. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.