Castalia, IA

ZIP code 52133 corresponds to the city of McGregor in Iowa. This small town is home to the Effigy Mounds National Monument, a significant archaeological site preserving Native American burial and ceremonial mounds. McGregor also features the historic McGregor-Marquette Bridge, which spans the Mississippi River and connects Iowa to Wisconsin. The scenic beauty of the surrounding bluffs and river make ZIP code 52133 a popular destination for outdoor enthusiasts.