Which is considered more prestigious overall: UIUC or Swarthmore College?

Swarthmore is more often viewed as the more prestigious institution in broad undergraduate academic and liberal-arts circles.

UIUC carries at least as much, and often more, prestige in several major fields, especially engineering, computer science, data-related fields, architecture, and some sciences and business areas.

Swarthmore suits a student seeking an intensely academic undergraduate experience built around small seminars, interdisciplinary exploration, writing, and close intellectual community.

UIUC fits a student who wants the resources of a major research university: a wide course catalog, large-scale labs, specialized programs, school spirit, and access to a much larger peer and alumni network. Neither name automatically outweighs the other in every context; the academic program and opportunities you use will matter more than a general prestige label.