About Grinnell College. Grinnell College in Grinnell, IA reports an overall acceptance rate of 14.5%, an early-round acceptance rate of 48.0%, an SAT middle 50% of 1410–1530, a class size of 438, and a yield of 31.0% based on the most recent Common Data Set filings. Self-governance tradition and open curriculum with no distribution requirements. One of the wealthiest LACs per student ($2B+ endowment for ~1,700 students), enabling generous need-blind aid.