<p>Capstone courses serve as a culminating experience in many Environmental Studies and Science (ESS) programs, providing opportunities for students to integrate knowledge and engage in applied or interdisciplinary work. Despite their central role in ESS curricula, there is limited empirical research examining how capstones are structured across institutions and how instructors design them in practice. This study uses a two-stage mixed-methods approach to examine how ESS Capstones are organized across programs, what recurring design considerations instructors describe, and how institutional constraints shape what forms of capstone work are possible. Survey data provide a broad descriptive overview of capstone structures and program characteristics, while follow-up interviews offer deeper insight into how instructors make decisions about course design and the tradeoffs they navigate in implementing these courses. Results indicate substantial variation in the primary forms of student engagement that organize capstone experiences, including original research, stakeholder-engaged projects, internships, and literature-based synthesis. Courses frequently incorporate multiple forms of engagement and a range of assessment strategies, with no consistent alignment between engagement type and assignment structure. Interview findings highlight recurring design considerations—such as topic selection, student work arrangements, course length, and preparatory coursework—as well as structural constraints related to faculty expertise, institutional policies, and available resources. Together, these findings suggest that ESS capstone design is highly context-dependent and shaped by an ongoing negotiation between pedagogical goals, faculty expertise, and institutional conditions. This study contributes a descriptive foundation for understanding variation in ESS capstones and identifies key considerations that may inform future research and program-level reflection on capstone design in interdisciplinary contexts.</p>