Mason & Jansen
Operator of record for 10 catalogued wells across 1 state. Every well below links to its full registry page.
At a glance
Mason & Jansen is the operator of record for 10 catalogued U.S. oil & gas wells in 1 state. 1 (10%) are active, 9 (90%) plugged & abandoned. Its largest concentration is in Illinois, with 10 wells (100% of its portfolio).
Wells operated
10
Active
1
Plugged
9
Orphaned
0
Portfolio by state
| State | Wells |
|---|---|
| Illinois | 10 |
Well mix
- Oil wells
- 0
- Gas wells
- 6
- Shut-in
- 0
- Active share
- 10%
Is this your company?
Claim Mason & Jansen to keep this portfolio accurate — verified operators can correct well statuses and add plugging documentation.
Claim your operator profileWhere does Mason & Jansen operate?
Mason & Jansen's catalogued wells are spread across 1 state: Illinois (10). Its 10 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 Mason & Jansen’s wells are active, plugged or orphaned?
10% of Mason & Jansen's catalogued wells are active, 19 percentage points below the national share of 29%. 90% are plugged & abandoned, against 47% nationally. None of the wells filed under this name is flagged as orphaned.
What kinds of wells does Mason & Jansen operate?
By product class, 0 (0%) are oil wells and 6 (60%) gas wells; nationally the shares are 43% and 17%. The deepest of its wells with a published depth is Longlett 1 in Adams, IL at 488 ft.
Notable wells operated by Mason & Jansen
| Well | API # / state ID | Status | Type | Location | Operator | Depth |
|---|---|---|---|---|---|---|
| Longlett 1 | 12-001-22224 | Plugged & abandoned | Other type | Adams, IL | Mason & Jansen | 488 ft |
| Harkness & Hoffman 1 | 12-001-22228 | Plugged & abandoned | Other type | Adams, IL | Mason & Jansen | 487 ft |
| Oitker 1 | 12-001-22227 | Active | Gas | Adams, IL | Mason & Jansen | 449 ft |
| Davidson & Wellman 1 | 12-001-22197 | Plugged & abandoned | Gas | Adams, IL | Mason & Jansen | 423 ft |
| Rabe 1 | 12-001-22232 | Plugged & abandoned | Other type | Adams, IL | Mason & Jansen | 420 ft |
| Jansen 2 | 12-001-22188 | Plugged & abandoned | Gas | Adams, IL | Mason & Jansen | 420 ft |
| Rottman 1 | 12-001-22211 | Plugged & abandoned | Gas | Adams, IL | Mason & Jansen | 411 ft |
| Longlett 1 | 12-001-22198 | Plugged & abandoned | Other type | Adams, IL | Mason & Jansen | 410 ft |
| Speckhart 1 | 12-001-22233 | Plugged & abandoned | Gas | Adams, IL | Mason & Jansen | 404 ft |
| Jansen 1 | 12-001-22186 | Plugged & abandoned | Gas | Adams, IL | Mason & Jansen | 400 ft |
Deepest first where depth is published. See all 10 wells →
Frequently asked questions
How many wells does Mason & Jansen operate?
Mason & Jansen is the operator of record for 10 catalogued oil & gas wells, with the largest concentration in Illinois (10). Only wells in states WellCensus has ingested are counted.
How many of Mason & Jansen's wells are still active?
1 of Mason & Jansen's catalogued wells are active; 9 are plugged & abandoned.
In which states does Mason & Jansen operate wells?
Mason & Jansen is the operator of record for wells in Illinois (10).
Does Mason & Jansen operate mostly oil or gas wells?
0 of Mason & Jansen's catalogued wells are oil wells and 6 are gas wells; the rest are injection, service or unclassified wells.
What is Mason & Jansen's deepest well?
Among wells with a published depth, Longlett 1 in Adams, IL is the deepest at 488 ft.
Where Mason & Jansen'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, “Mason & Jansen — well portfolio”, https://wellcensus.com/operators/mason-jansen-91096 (data as of October 10, 2026).
Dataset updated . Operator portfolios are resolved from raw state registry filings (exact-normalized names; subsidiaries stay separate).