Plymouth County is the westernmost county in the U.S. state of Iowa. As of the 2020 census, the population was 25,698, and was estimated to be 25,697 in 2025. The county seat and the largest city is Le Mars. Plymouth County was named after Plymouth, Massachusetts.
- Country
- United States
- Inception
- 1851
- Website
- https://www.co.plymouth.ia.us/
