Is University of Illinois Urbana-Champaign or UMass Amherst harder to get into for undergraduates?

The biggest practical tradeoff is that UIUC is more unevenly selective by major, while UMass Amherst is competitive but usually less extreme across most undergraduate programs. In broad terms, UIUC is harder to get into overall for many applicants, and that gap becomes especially noticeable in high-demand majors like engineering, computer science, and business. UMass Amherst is still selective, but it is typically viewed as the more accessible of the two for general undergraduate admission.

A lot of this comes down to how strongly UIUC admits by program. At UIUC, your intended major can change your odds quite a bit, and some colleges there are much tougher than the university-wide picture suggests. UMass also has stronger and weaker programs, but the swings are usually not as dramatic.

For a typical applicant applying to non-flagship majors, UIUC still tends to be the tougher admit. Its applicant pool is very large, it draws heavily from both in-state and out-of-state students, and certain programs have national-level demand. UMass Amherst has a solid reputation and can be competitive, especially for popular majors, but it is not usually placed in the same level of selectivity pressure as UIUC.

If you are comparing plain admit odds without focusing on one specific major, I would treat UIUC as the harder school to enter. If your intended major is something especially sought-after at UIUC, the difference becomes even more pronounced.