If your son studies science, math or any of the liberal arts at an academically rigorous college he will be challenged, both in the classroom and outside of it in informal interaction with his classmates.
He should take a look at Williams – Excellent sciences and overall academics; multi-talented, energetic and intellectually lively student body; strong track record for placement at top graduate and professional schools (with personalized advising); widespread involvement in outdoorsy activities and probably more Eagle Scouts per square mile than anywhere on the planet.