The MGSC Mumford Hill Field site was one of three Enhanced Oil Recovery (EOR) field validation tests conducted by the MGSC to assess potential for CO2 storage in oil in the Illinois Basin. The project was supported by the U.S. Department of Energy (DE-FC26-05NT42588) and the Illinois Department of Commerce and Economic Opportunity. CO2 was injected at the Mumford Hills Field test site in Posey County, IN through an existing well into the Clore Formation, an oil-bearing sandstone interval at about 1,900 feet deep. A cumulative 6,950 tons of CO2 was injection at a rate of 20–35 tons per day and increased oil production in surrounding wells. Approximately 0.5% of the injected CO2 was produced at the surface through September 2011, and 99.5% of the injected CO2 was stored. Baseline, injection, and post-injection monitoring were conducted until one year after the CO2 injection termination.