Which is better for undergraduate research, Williams or Princeton?

For undergraduate research specifically, Princeton usually offers the broader range of opportunities. It is a major research university, and undergrads can get involved through department-based research and the senior thesis, which are deeply built into the academic culture. Williams is also excellent, but its strength is different: closer faculty access, smaller-scale projects, and a more intimate academic environment.

Princeton tends to fit students who want to start exploring a lot of possible research directions, especially in STEM, economics, public policy, or other fields where a university setting creates more active labs and institutes. There are simply more research centers, more graduate-level infrastructure, and more faculty running ongoing projects. If you like the idea of joining a lab early, working with advanced equipment, or finding a niche area that may not exist at a small college, Princeton has the edge.

Williams is especially appealing for students who want research to feel personal rather than institutional. Because it is a liberal arts college with no graduate students, faculty attention is concentrated on undergraduates, and students often work very directly with professors. In many humanities and social science fields, that can be a real advantage. You may have fewer total projects to choose from than at Princeton, but the barrier to becoming meaningfully involved can feel lower because professors are hiring and mentoring only undergrads.

If your definition of research includes independent scholarship, close reading, archival work, original writing, or one-on-one collaboration with a professor, Williams can be outstanding. If your definition leans toward formal lab research, larger teams, and a wider institutional research ecosystem, Princeton is stronger.