Which feels more like a small school, WashU or Williams?

Williams will feel more like a small school. It is a liberal arts college with a much smaller undergraduate community, most classes are centered on undergrads, and faculty interaction is built into the academic structure in a way that is hard for a larger research university to match. Day to day, that usually translates into more familiar faces, smaller class discussions, and a campus culture where students are more likely to know people across different years and interests.

One big difference is the classroom experience. At Williams, the curriculum is designed around undergraduates, and the school is especially known for tutorials and discussion-based classes that create regular, direct contact with professors. WashU also has many small classes, especially after intro courses, but it is still a mid-sized research university, so the overall academic environment feels less intimate than Williams.

Another differentiator is the scale of the student body and campus social life. Williams is in a small town and has a more contained residential environment, so campus life tends to revolve around the college itself. That often makes the community feel tight-knit in a very visible way. WashU has a cohesive campus too, but being in St. Louis and having more students, more schools, and a broader university structure gives it a more expansive feel.

Professor access is strong at both places, but Williams has the edge if your main question is personal attention. At WashU, students can absolutely build close faculty relationships, especially within their major, yet the institution still operates with the rhythms of a larger university. Williams is more likely to feel like the kind of place where professors know students quickly and where the campus culture consistently reinforces that smaller, more personal atmosphere.