Cl Mcmahon
Operator of record for 76 catalogued wells across 1 state. Every well below links to its full registry page.
At a glance
Cl Mcmahon is the operator of record for 76 catalogued U.S. oil & gas wells in 1 state. 5 (7%) are active, 56 (74%) plugged & abandoned and 1 flagged as orphaned. Its largest concentration is in Illinois, with 76 wells (100% of its portfolio).
Wells operated
76
Active
5
Plugged
56
Orphaned
1
Portfolio by state
| State | Wells |
|---|---|
| Illinois | 76 |
Well mix
- Oil wells
- 36
- Gas wells
- 1
- Shut-in
- 0
- Active share
- 7%
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Claim your operator profileWhere does Cl Mcmahon operate?
Cl Mcmahon's catalogued wells are spread across 1 state: Illinois (76). Its 76 Illinois wells are 0.0% of the 174,478 catalogued in that state — its largest share of any state. Counts cover only states whose registries WellCensus has ingested with operator names; wells in Nebraska and Texas (location indexes) and in states without a registry ingest are not yet attributed to any operator.
How many of Cl Mcmahon’s wells are active, plugged or orphaned?
7% of Cl Mcmahon's catalogued wells are active, 22 percentage points below the national share of 29%. 74% are plugged & abandoned, against 47% nationally. 1 wells filed under this name are flagged as orphaned — unplugged, with no operator able to plug them.
What kinds of wells does Cl Mcmahon operate?
By product class, 36 (47%) are oil wells and 1 (1%) gas wells; nationally the shares are 43% and 17%. The deepest of its wells with a published depth is Smith, Emma 25 in Clark, IL at 564 ft.
Notable wells operated by Cl Mcmahon
| Well | API # / state ID | Status | Type | Location | Operator | Depth |
|---|---|---|---|---|---|---|
| Smith, Emma 25 | 12-023-02528 | Plugged & abandoned | Oil | Clark, IL | C. L. McMahon, Inc. | 564 ft |
| Howard, Wm. L-7 | 12-023-02633 | Plugged & abandoned | Oil | Clark, IL | C. L. McMahon, Inc. | 557 ft |
| Cole & Daley O-1 | 12-023-00684 | Plugged & abandoned | Oil | Clark, IL | C. L. McMahon, Inc. | 555 ft |
| Huffman, George W. 1 | 12-023-02628 | Other status | Other type | Clark, IL | C. L. McMahon, Inc. | 550 ft |
| Smith, Emma 29 | 12-023-02532 | Plugged & abandoned | Oil | Clark, IL | C. L. McMahon, Inc. | 546 ft |
| Phillips, C. H-13 | 12-023-02465 | Active | Injection | Clark, IL | C. L. McMahon, Inc. | 542 ft |
| Cole & Daley M-7 | 12-023-01399 | Plugged & abandoned | Injection | Clark, IL | C. L. McMahon, Inc. | 542 ft |
| Smith, Emma 1-8 | 12-023-02535 | Plugged & abandoned | Injection | Clark, IL | C. L. McMahon, Inc. | 542 ft |
| English, L.C. 12 | 12-023-00688 | Plugged & abandoned | Other type | Clark, IL | C. L. McMahon, Inc. | 541 ft |
| Lamb, Ovetha P-7 | 12-023-02621 | Plugged & abandoned | Oil | Clark, IL | C. L. McMahon, Inc. | 541 ft |
| Cole & Daley L-7A | 12-023-02444 | Plugged & abandoned | Injection | Clark, IL | C. L. McMahon, Inc. | 535 ft |
| Smith, Emma 1-10A | 12-023-02536 | Plugged & abandoned | Oil | Clark, IL | C. L. McMahon, Inc. | 535 ft |
Deepest first where depth is published. See all 76 wells →
Frequently asked questions
How many wells does Cl Mcmahon operate?
Cl Mcmahon is the operator of record for 76 catalogued oil & gas wells, with the largest concentration in Illinois (76). Only wells in states WellCensus has ingested are counted.
How many of Cl Mcmahon's wells are still active?
5 of Cl Mcmahon's catalogued wells are active; 56 are plugged & abandoned and 1 are flagged as orphaned.
In which states does Cl Mcmahon operate wells?
Cl Mcmahon is the operator of record for wells in Illinois (76).
Does Cl Mcmahon operate mostly oil or gas wells?
36 of Cl Mcmahon's catalogued wells are oil wells and 1 are gas wells; the rest are injection, service or unclassified wells.
What is Cl Mcmahon's deepest well?
Among wells with a published depth, Smith, Emma 25 in Clark, IL is the deepest at 564 ft.
Where Cl Mcmahon's wells are
About this data
Source: State oil & gas regulator registries (operator of record as filed, exact-normalized across states) plus the USGS United States Documented Orphaned Well Database (2026), as published October 10, 2026 — WellCensus refreshes it monthly. See the methodology for how records are matched, cleaned and scored.
Cite as: WellCensus, “Cl Mcmahon — well portfolio”, https://wellcensus.com/operators/cl-mcmahon-66095 (data as of October 10, 2026).
Dataset updated . Operator portfolios are resolved from raw state registry filings (exact-normalized names; subsidiaries stay separate).