Sense of community (SoC) positively promotes persistence and graduation rates of college students by helping them to feel cared about by others, accepted as members of the campus community, and that they matter to their peers and other community members (Cheng, 2004; Harris, 2007a; Schlossberg, 1989). The college union is one of the most influential settings in developing SoC (Barrett, 2014; Janisz, 2014; Maxwell, 2016; Smyth, 2016) and improving student persistence (Tierno, 2013). However, scholars and educators lack understanding of the ways in which the physical and organizational environments of college unions contribute to SoC development among students. The purpose of this narrative study (Clandinin, 2013) was to understand the role of the college union in developing SoC among college students. Anchored in a modified version of Strange and Banning's (2015) campus ecology framework, the study explored how physical and organizational environments within a college union influenced the community conditions necessary for supporting the educational purposes of student engagement and learning. To understand the role of the physical and organizational environments of the college union in students' SoC development, this study used photo-elicitation methods and semi-structured interviews with seven participants from one large, public, historically White university with high research activity. Students' stories revealed a College Union Sense of Community (CU-SoC) Actualization Model in which students progressed through developmental stages: feeling overwhelmed initially, connecting with campus sub-communities, building localized community, and deepening connections and strengthening bonds with administrators and peers. By progressing through these stages, students developed a SoC toward the institution. The data also highlighted how the college union's physical and organizational environments advanced the SoC development process by creating a home-like feeling, encouraging and enhancing interactions through design, cultivating lasting memories, and nurturing a student-centered culture. These findings represent a narrative account describing the students' personal experiences in relation to how the college union shaped their SoC. / Ph. D.