Who operates the most oil and gas wells in the United States?

Historic Owner is the largest operator in the WellCensus registry with 118,046 catalogued wells across 1 state (18,978 active).

How many oil and gas well operators are there in the US?

WellCensus resolves 101,832 canonical operators from raw state filings across KS, OK, CA, OH, LA, PA, KY, IL, NM, WY, CO, WV, MI, NY, ND, MT, UT, MS, AR, AL — subsidiaries are kept separate (no fuzzy merging).

Largest well operators in America

The 100 largest operators by catalogued wells, resolved across the 20 ingested state registries (KS, OK, CA, OH, LA, PA, KY, IL, NM, WY, CO, WV, MI, NY, ND, MT, UT, MS, AR, AL). State placeholder records are excluded — see methodology.

Dataset updated October 2026 . Derived from public data sources.

100 largest U.S. oil & gas well operators by catalogued wells
#	Operator	Wells	Active	Plugged	States
1	Historic Owner	118,046	18,978	67,274	OH
2	Chevron USA	65,303	13,921	43,648	AL AR CA CO KS LA MI ND NM OH OK PA UT WV WY
3	Aera Energy	57,745	13,425	35,647	CA
4	Inactive Operator	45,271	0	39,755	LA
5	Diversified Production	31,363	28,431	688	AL KY LA OH OK WV
6	Diversified Prod	21,609	17,980	406	PA
7	Hilcorp Energy	19,950	15,820	2,086	AL CO LA MS NM OH PA WY
8	Eog Resources	16,762	2,897	4,127	AR CA CO KS LA MI MS MT ND NM NY OH OK PA UT WV WY
9	Pa Dep Ofc Oil & Gas Mgmt	12,967	0	3,391	PA
10	Scout Energy Management	12,456	9,882	1,040	CO KS MT ND NM OK UT
11	California Resources Production	11,525	3,004	5,092	CA
12	Kerr Mcgee Oil & Gas Onshore	11,405	2,600	5,745	CO KS LA ND NM OK UT WY
13	Berry Petroleum	11,021	3,375	3,765	AR CA CO IL KS KY OK UT WY
14	Sentinel Peak Resources California	10,941	4,004	4,811	CA
15	Noble Energy	10,764	1,646	6,368	CA CO IL KS LA MT NM OK PA UT WV WY
16	Texaco	10,522	267	9,120	AL AR CA CO IL KS KY LA MI MS MT ND NY OH OK PA UT
17	California Resources Elk Hills	10,483	4,160	3,634	CA
18	Ohio Oil Co The	9,957	3,178	2,989	IL
19	Citation Oil & Gas	9,922	7,334	1,384	CO IL KS LA MS MT ND NM OK UT WY
20	Quaker State	9,033	0	8,755	NY PA WV
21	Marathon Oil	8,999	2,695	5,360	AR CA CO IL KS KY LA MI MS MT ND NM OK PA UT WV WY
22	Tep Rocky Mountain	8,976	6,818	175	CO
23	Pdc Energy	8,577	2,373	3,813	CO KS OH
24	Devon Energy Production	8,543	2,543	2,077	CO KS LA MI MT ND NM OH OK WY
25	Carbon Creek Energy	8,498	1,101	1,751	WY
26	Oxy USA	7,402	1,691	4,023	AR CA CO KS KY LA MI MS MT ND NM OK UT WV WY
27	Merit Energy	7,361	4,338	986	AR CA CO KS LA MI MT ND NM OK UT WY
28	Ows Acquisition	7,259	7,109	59	OH PA WV
29	Xto Energy	6,846	2,814	1,953	AR CO KS KY LA MT ND NM NY OH OK PA UT WV WY
30	Continental Resources	6,747	4,292	867	CO IL KS KY LA MI MS MT ND NM OH OK WY
31	Pennzoil Prod	6,722	0	6,368	PA
32	Riverside Energy Michigan	6,468	5,562	415	MI
33	Qb Energy Operating	6,030	3,984	398	CO
34	Eqt Production	5,832	2,829	1,011	KY OH WV
35	Rj Energy	4,921	2,758	2,015	KS OK
36	Bp America Production	4,672	20	4,004	CO KS LA MI NM OH OK UT WY
37	Denbury Onshore	4,651	1,936	1,318	AL LA MS MT ND WY
38	Kentucky West Virginia Gas	4,645	2,935	1,460	KY
39	Contango Resources	4,548	1,546	686	LA MT NM OK WY
40	E & B Natural Resources Management	4,502	1,478	1,039	CA KS WY
41	Mewbourne Oil	4,472	1,876	375	KS NM OK
42	Ultra Resources	4,247	3,456	84	CO PA UT WY
43	Range Resources Appalachia	4,233	1,750	593	NY OH PA WV
44	Shell Oil	4,222	139	3,552	AL AR CA CO IL KS KY LA MI MS MT ND NM NY OK PA UT WY
45	Anadarko E&p Onshore	4,207	66	2,149	CO LA ND PA UT WY
46	Chesapeake Appalachia	4,177	510	546	AL KY NY OH PA WV
47	Flywheel Energy Production	3,963	3,715	140	AR
48	Conoco	3,950	4	3,730	AL AR CA CO IL KS KY LA MI MS MT ND NM OK UT WY
49	Own Resources Operating	3,947	3,719	176	CO KS
50	Columbia Gas Transmission	3,934	3,065	808	KY NY OH WV
51	Crowheart Energy	3,925	2,487	466	CO WY
52	Enervest Production Partners	3,888	2,649	29	LA
53	Urban Oil & Gas Group	3,886	3,113	451	AL AR IL LA OK UT WY
54	Minard Run Oil	3,861	1,645	1,953	IL NY PA
55	Simcoe	3,787	3,566	93	CO NM
56	Koda Gnb	3,674	2,444	818	UT
57	Phillips Petroleum	3,654	36	3,013	AL AR CA CO IL KS KY LA MI MS MT ND NM UT WY
58	Pa Gen Energy	3,537	232	2,937	PA
59	Colt Energy	3,497	1,174	1,761	KS LA MS
60	Expand Operating	3,488	3,050	24	LA OH WV
61	Chesapeake Operating	3,485	156	2,580	AR CO KS KY LA MT ND NM OK UT WY
62	Eiger Operating	3,477	2,889	3	KS OK
63	Union Oil Company Of California	3,476	119	3,097	AL CA CO IL KS MT ND NY
64	Apache	3,404	566	2,360	AL AR CA CO KS LA MI MS MT ND NM NY OK PA UT WY
65	Freeport Sulphur	3,392	0	3,281	LA MS
66	Burlington Resources Oil & Gas	3,385	969	1,584	CO KS MT ND NM OK
67	Ashland Oil & Refining	3,332	910	1,702	AR CO IL KY LA MS ND NY
68	Ohio Oil	3,174	783	1,681	AL AR CO IL KY MI MS MT ND UT
69	Bce Mach	3,143	2,809	74	KS OK
70	Conocophillips	3,140	64	2,347	CA LA MT ND NM OK UT WY
71	Exxon	3,035	476	2,096	AL AR CA IL KY LA MI MT PA UT
72	Murfin Drilling	3,005	973	1,882	CO KS MT ND OK
73	Cog Operating	3,004	815	761	NM
74	Whiting Oil And Gas	2,987	1,796	580	AR CA KS LA MI MT ND NM OK
75	Carter Oil	2,966	324	1,119	AR CO IL KY MI MS MT ND UT WY
76	Pure Oil	2,920	231	1,887	AR CO IL KY LA MI MS MT ND OK PA UT WY
77	Hess Bakken Investments Ii	2,903	1,781	497	ND
78	Texas Petroleum Investment	2,887	832	317	AL LA MS
79	Greenway Energy	2,882	2,731	26	NY PA
80	Coterra Energy Operating	2,878	1,165	282	NM OK
81	Seneca Resources	2,869	1,187	838	AL CA LA NY PA
82	American Warrior	2,848	1,129	1,214	KS OK
83	Jonah Energy	2,847	2,567	78	CO NM WY
84	Bce Mach Iii	2,829	2,590	46	KS NM OK
85	Eog Y Resources	2,824	0	1,688	NM WY
86	Gulf Oil	2,797	55	2,438	AL AR CA CO IL KY LA MI MS MT ND NM NY UT WY
87	Ridge Oil & Gas	2,770	2,497	10	KS MT
88	Eqt Prod	2,750	1,378	480	PA
89	Cleveland Cliffs Iron	2,687	0	9	MI
90	Expand Oper	2,665	2,648	9	PA
91	Eastern Gas Transmission And Storage	2,656	1,145	1,419	NY WV
92	Tidelands Oil Production	2,645	676	1,694	CA
93	Greylock Conventional	2,645	2,482	63	PA WV
94	Ows Energy	2,609	2,603	2	PA
95	Amoco Production	2,582	0	2,232	AL AR CA CO LA MI MS MT ND NY UT WV
96	East Resources	2,530	2	1,446	NY PA WV
97	Adamas Energy	2,503	1,074	0	LA
98	Shell Western E&p	2,500	0	2,064	AL CA KS LA ND
99	Evergreen Natural Resources	2,499	1,805	225	CO
100	River Rock Operating	2,463	2,017	388	KS OK