How competitive is University of Illinois Urbana-Champaign computer science admissions compared to other strong CS programs?

UIUC computer science should absolutely be treated as a reach for almost everyone. Its CS program is one of the most selective in the country, and in practice it is often comparable to other top-tier CS programs in difficulty, even if the overall university admit rate is much higher.

The key thing is that UIUC admissions are very major-specific. General admission to Illinois is not the same as admission to CS in Grainger. CS applicants are competing for a limited number of seats in a program with a huge national reputation, so the bar is much higher than for many other majors at UIUC.

Compared to other strong CS schools, UIUC CS is usually in the same conversation as places like Georgia Tech, Michigan CS, and other highly selective public flagship CS programs. It is not quite the same category as a school where every major is ultra-selective across the board, but for CS specifically, it is definitely a high-reach admissions outcome.

For most applicants, it belongs in the reach category.

What makes it especially tricky is that very qualified students get denied every year. Strong grades, high rigor, and excellent math preparation are expected, not distinguishing by themselves. If you apply, it helps to have clear evidence of real fit with CS, strong quantitative preparation, and well-executed essays that are specific to UIUC and the major.