The Illinois Basin is one of the oldest oil-producing regions in the United States, with commercial production dating back to the late 1800s. The basin covers approximately 60,000 square miles across southern Illinois, southwestern Indiana, and western Kentucky. While production volumes are modest compared to the major shale plays, the Illinois Basin remains an active producing region with thousands of stripper wells generating steady royalty income. We buy mineral rights, royalty interests, NPRI, and ORRI across the Illinois Basin.
Approximate location of the Illinois Basin shown in tan
Basin-level activity chart not yet available for the Illinois Basin. For current activity, see our rig count dashboard and the state production pages linked above.
The Illinois Basin is a broad structural depression filled with Paleozoic sediments up to 15,000 feet thick. The primary productive formations include the Mississippian-age Aux Vases Sandstone, Ste. Genevieve Limestone, and Salem Limestone, plus the Pennsylvanian-age Cypress and Paint Creek formations. Most production comes from conventional sandstone and carbonate reservoirs at depths of 1,500 to 4,000 feet. The New Albany Shale, the organic-rich source rock for the basin, has attracted some unconventional interest but has not been commercially developed at scale. Oil in the Illinois Basin is generally medium-gravity (30 to 38 API) sweet crude.
The Illinois Basin is dominated by small independent operators and family-owned companies rather than the large publicly traded companies that dominate the major shale plays. Rex Energy, Tri-Star, and Gallagher Drilling are among the more active operators, along with numerous small independents running one to ten rigs. The small-operator character of the basin means that mineral owners may deal with less sophisticated operators, but it also means that there is a broad base of operators willing to drill lower-volume conventional wells.
Illinois Basin mineral values reflect the conventional character of the basin — lower per-well production rates compared to major shale plays, but also lower drilling costs and very long-lived production. Key value drivers include current production levels, the number of producing wells, remaining reserve life, and whether enhanced recovery (waterflooding) is in place. Owners with larger acreage positions across multiple producing fields can generate meaningful aggregate royalty income even though individual well rates are modest.
Additional counties we cover within the Illinois Basin, sorted by recent oil and gas activity:
Yes, though at a much lower pace than the major shale plays. Small independent operators continue to drill conventional vertical wells targeting the Aux Vases, Ste. Genevieve, and other Mississippian and Pennsylvanian formations. Enhanced oil recovery (waterflooding) is also common, extending the productive life of existing fields. The basin sees 50 to 150 new well permits per year in an average commodity price environment.
Illinois Basin minerals are conventional — they produce from traditional sandstone and limestone reservoirs via vertical wells, not from shale formations via horizontal wells. This means lower per-well production rates but also lower drilling costs. The economics are different from shale plays, and the valuation approach reflects the mature, steady-decline character of conventional production rather than the high-initial-rate, steep-decline profile of shale wells.
Illinois has a compulsory pooling statute that allows operators to pool unleased mineral interests in a drilling unit. However, forced pooling is less common in the Illinois Basin than in major shale plays because most drilling is on voluntary leases. If you receive a pooling notice, understanding your options is important — we can help you evaluate whether selling is a better option than participating.