{"data":{"state":"IL","sourceDates":{"ranges":[{"key":"operators","label":"Operator rankings","oldest":"2026-09-16","newest":"2026-09-16"},{"key":"permits","label":"Permit records","oldest":"2026-07-25","newest":"2026-09-17"},{"key":"ducs","label":"DUC records","oldest":null,"newest":null},{"key":"spuds","label":"Spud records","oldest":null,"newest":null},{"key":"producers","label":"Producing-well records","oldest":null,"newest":null},{"key":"counties","label":"County activity","oldest":"2026-09-16","newest":"2026-09-16"},{"key":"formations","label":"Formation summaries","oldest":"2026-09-16","newest":"2026-09-16"}],"complete":false,"oldest":"2026-07-25","newest":"2026-09-17"},"marketDataDateRange":null,"counts":{"permits24mo":456,"ducCount":0,"recentSpuds90d":0,"newProducers6mo":0,"activeCounties":102,"activeFormations":5,"rankedOperators":100,"totalWellsTopOperators":85407},"topOperators":[{"rank":1,"operatorSlug":"the-ohio-oil","operatorName":"THE OHIO OIL","wellCount":10782,"recentPermitCount":0,"ducCount":0,"topFormation":"Illinois Basin","topCounty":"CRAWFORD"},{"rank":2,"operatorSlug":"marathon-oil-company","operatorName":"MARATHON OIL COMPANY","wellCount":4529,"recentPermitCount":0,"ducCount":0,"topFormation":"Illinois Basin","topCounty":"LAWRENCE"},{"rank":3,"operatorSlug":"the-texas-company","operatorName":"THE TEXAS COMPANY","wellCount":4094,"recentPermitCount":0,"ducCount":0,"topFormation":"Illinois Basin","topCounty":"MARION"},{"rank":4,"operatorSlug":"pure-oil-company","operatorName":"PURE OIL COMPANY","wellCount":3223,"recentPermitCount":0,"ducCount":0,"topFormation":"Illinois Basin","topCounty":"RICHLAND"},{"rank":5,"operatorSlug":"texaco","operatorName":"TEXACO","wellCount":2427,"recentPermitCount":0,"ducCount":0,"topFormation":"Illinois Basin","topCounty":"MARION"},{"rank":6,"operatorSlug":"ohio-oil-company","operatorName":"OHIO OIL COMPANY","wellCount":2181,"recentPermitCount":0,"ducCount":0,"topFormation":"Illinois Basin","topCounty":"CRAWFORD"},{"rank":7,"operatorSlug":"the-pure-oil-company","operatorName":"THE PURE OIL COMPANY","wellCount":1935,"recentPermitCount":0,"ducCount":0,"topFormation":"Illinois Basin","topCounty":"WAYNE"},{"rank":8,"operatorSlug":"the-carter-oil","operatorName":"THE CARTER OIL","wellCount":1812,"recentPermitCount":0,"ducCount":0,"topFormation":"Illinois Basin","topCounty":"FAYETTE"},{"rank":9,"operatorSlug":"forest-oil","operatorName":"FOREST OIL","wellCount":1678,"recentPermitCount":0,"ducCount":0,"topFormation":"Illinois Basin","topCounty":"CUMBERLAND"},{"rank":10,"operatorSlug":"magnolia-petroleum-company","operatorName":"MAGNOLIA PETROLEUM COMPANY","wellCount":1605,"recentPermitCount":0,"ducCount":0,"topFormation":"Illinois Basin","topCounty":"MARION"}],"topCounties":[{"county":"LAKE","countySlug":null,"totalWells":31424,"recentPermitCount":0,"recentSpudCount":0,"ducCount":0,"topOperatorSlug":"il-state-geological-survey","topOperatorName":"IL STATE GEOLOGICAL SURVEY","topFormation":"Michigan Basin"},{"county":"CRAWFORD","countySlug":"crawford-il","totalWells":28731,"recentPermitCount":43,"recentSpudCount":0,"ducCount":0,"topOperatorSlug":"the-ohio-oil","topOperatorName":"THE OHIO OIL","topFormation":"Illinois Basin"},{"county":"WILL","countySlug":null,"totalWells":25446,"recentPermitCount":0,"recentSpudCount":0,"ducCount":0,"topOperatorSlug":"il-state-geological-survey","topOperatorName":"IL STATE GEOLOGICAL SURVEY","topFormation":"Wisconsin Arch"},{"county":"MC HENRY","countySlug":null,"totalWells":24295,"recentPermitCount":0,"recentSpudCount":0,"ducCount":0,"topOperatorSlug":"il-state-geological-survey","topOperatorName":"IL STATE GEOLOGICAL SURVEY","topFormation":"Wisconsin Arch"},{"county":"WHITE","countySlug":"white-il","totalWells":18588,"recentPermitCount":148,"recentSpudCount":0,"ducCount":11,"topOperatorSlug":"superior-oil-company","topOperatorName":"SUPERIOR OIL COMPANY","topFormation":"Illinois Basin"},{"county":"LAWRENCE","countySlug":"lawrence-il","totalWells":18007,"recentPermitCount":6,"recentSpudCount":0,"ducCount":0,"topOperatorSlug":"the-ohio-oil","topOperatorName":"THE OHIO OIL","topFormation":"Illinois Basin"},{"county":"COOK","countySlug":null,"totalWells":17440,"recentPermitCount":0,"recentSpudCount":0,"ducCount":0,"topOperatorSlug":"illinois-state-geological-survey","topOperatorName":"ILLINOIS STATE GEOLOGICAL SURVEY","topFormation":"Michigan Basin"},{"county":"WAYNE","countySlug":"wayne-il","totalWells":15406,"recentPermitCount":2,"recentSpudCount":0,"ducCount":0,"topOperatorSlug":"the-pure-oil-company","topOperatorName":"THE PURE OIL COMPANY","topFormation":"Illinois Basin"},{"county":"PEORIA","countySlug":"peoria","totalWells":14725,"recentPermitCount":0,"recentSpudCount":0,"ducCount":0,"topOperatorSlug":"central-il-light-company","topOperatorName":"CENTRAL IL LIGHT COMPANY","topFormation":"Illinois Basin"},{"county":"KANE","countySlug":null,"totalWells":13722,"recentPermitCount":0,"recentSpudCount":0,"ducCount":0,"topOperatorSlug":"il-state-geological-survey","topOperatorName":"IL STATE GEOLOGICAL SURVEY","topFormation":"Wisconsin Arch"}],"topFormations":[{"formationSlug":"illinois-basin","formationName":"Illinois Basin","wellCount":199349,"activeOperators":13021,"recentPermits24Mo":502},{"formationSlug":"wisconsin-arch","formationName":"Wisconsin Arch","wellCount":3692,"activeOperators":336,"recentPermits24Mo":15},{"formationSlug":"michigan-basin","formationName":"Michigan Basin","wellCount":621,"activeOperators":98,"recentPermits24Mo":0},{"formationSlug":"new-albany","formationName":"New Albany","wellCount":477,"activeOperators":264,"recentPermits24Mo":0},{"formationSlug":"lake-michigan","formationName":"Lake Michigan","wellCount":61,"activeOperators":5,"recentPermits24Mo":0}],"recentPermits":[{"operatorSlug":"ameren-illinois-company","permitDate":"2026-07-30","apiNumber":"121212856800","county":"MARION","wellName":"Centralia 3-HOR","formation":"Illinois Basin"},{"operatorSlug":"ameren-illinois-company","permitDate":"2026-07-29","apiNumber":"121212856700","county":"MARION","wellName":"Centralia 2-HOR","formation":"Illinois Basin"},{"operatorSlug":"keyrock-energy","permitDate":"2026-07-28","apiNumber":"121992422000","county":"WILLIAMSON","wellName":"OBC 25-3","formation":"Illinois Basin"},{"operatorSlug":"schwartz-oil-properties","permitDate":"2026-07-27","apiNumber":"121212857000","county":"MARION","wellName":"Howell 7-B HOR","formation":"Illinois Basin"},{"operatorSlug":"ameren-illinois-company","permitDate":"2026-07-27","apiNumber":"121633175100","county":"ST CLAIR","wellName":"Freeburg 19-HOR","formation":"Illinois Basin"},{"operatorSlug":"stewart-producers","permitDate":"2026-07-27","apiNumber":"120552533600","county":"FRANKLIN","wellName":"Illinois Minerals 19-1","formation":"Illinois Basin"},{"operatorSlug":"schwartz-oil-properties","permitDate":"2026-07-27","apiNumber":"121212856900","county":"MARION","wellName":"Howell 6-C HOR","formation":"Illinois Basin"},{"operatorSlug":"keyrock-energy","permitDate":"2026-07-23","apiNumber":"121672843500","county":"SANGAMON","wellName":"Boarman 6","formation":"Illinois Basin"},{"operatorSlug":"keyrock-energy","permitDate":"2026-07-23","apiNumber":"121672843400","county":"SANGAMON","wellName":"Boarman 7","formation":"Illinois Basin"},{"operatorSlug":"gesells-pump-sales-service","permitDate":"2026-07-23","apiNumber":"120552533800","county":"FRANKLIN","wellName":"Harrelson 1-A","formation":"Illinois Basin"}],"recentSpuds":[],"newProducers":[],"ducs":[],"dataAsOf":"2026-09-17"},"meta":{"apiVersion":"1.0","state":"IL","source":"Illinois Department of Natural Resources (IDNR)"}}