Ullin is located in southern Illinois in Pulaski County between Jonesboro and Mound City along Highway 51 on the banks of the Cache River about 15 miles east of the Mississippi River and 10 miles north of the Ohio River. The population estimate for July 1, 1998 was 507, an increase of 105 since 1990.
The town's residents and area visitors enjoy nearby Cypress Creek NWR. In addition, the southwest portion of the Shawnee National Forest is only about 5 miles west of town.
