Reference

Minnesota API county codes

Every Minnesota API well number starts with 22, the state code. The next three digits are the county code, one of the 87 listed below, so a number beginning 22-001 belongs to a well in Aitkin County.

To decode a whole number, including the sidetrack and completion digits, paste it into the API well number decoder.

How to read a Minnesota API number

22State: Minnesota

001County: Aitkin

12345Well, unique within the county

The first ten digits identify one well. Two more digits can follow for a sidetrack, and two after that for a later completion. The county is the one where the well starts at the surface, so a horizontal well that crosses a county line keeps its surface county's code. A few state regulators assign the producing county instead, so the state record is the final word on a well near a boundary.

All 87 Minnesota counties

County code	County	API numbers start
001	Aitkin	22-001-
003	Anoka	22-003-
005	Becker	22-005-
007	Beltrami	22-007-
009	Benton	22-009-
011	Big Stone	22-011-
013	Blue Earth	22-013-
015	Brown	22-015-
017	Carlton	22-017-
019	Carver	22-019-
021	Cass	22-021-
023	Chippewa	22-023-
025	Chisago	22-025-
027	Clay	22-027-
029	Clearwater	22-029-
031	Cook	22-031-
033	Cottonwood	22-033-
035	Crow Wing	22-035-
037	Dakota	22-037-
039	Dodge	22-039-
041	Douglas	22-041-
043	Faribault	22-043-
045	Fillmore	22-045-
047	Freeborn	22-047-
049	Goodhue	22-049-
051	Grant	22-051-
053	Hennepin	22-053-
055	Houston	22-055-
057	Hubbard	22-057-
059	Isanti	22-059-
061	Itasca	22-061-
063	Jackson	22-063-
065	Kanabec	22-065-
067	Kandiyohi	22-067-
069	Kittson	22-069-
071	Koochiching	22-071-
073	Lac qui Parle	22-073-
075	Lake	22-075-
077	Lake of the Woods	22-077-
079	Le Sueur	22-079-
081	Lincoln	22-081-
083	Lyon	22-083-
085	McLeod	22-085-
087	Mahnomen	22-087-
089	Marshall	22-089-
091	Martin	22-091-
093	Meeker	22-093-
095	Mille Lacs	22-095-
097	Morrison	22-097-
099	Mower	22-099-
101	Murray	22-101-
103	Nicollet	22-103-
105	Nobles	22-105-
107	Norman	22-107-
109	Olmsted	22-109-
111	Otter Tail	22-111-
113	Pennington	22-113-
115	Pine	22-115-
117	Pipestone	22-117-
119	Polk	22-119-
121	Pope	22-121-
123	Ramsey	22-123-
125	Red Lake	22-125-
127	Redwood	22-127-
129	Renville	22-129-
131	Rice	22-131-
133	Rock	22-133-
135	Roseau	22-135-
137	St. Louis	22-137-
139	Scott	22-139-
141	Sherburne	22-141-
143	Sibley	22-143-
145	Stearns	22-145-
147	Steele	22-147-
149	Stevens	22-149-
151	Swift	22-151-
153	Todd	22-153-
155	Traverse	22-155-
157	Wabasha	22-157-
159	Wadena	22-159-
161	Waseca	22-161-
163	Washington	22-163-
165	Watonwan	22-165-
167	Wilkin	22-167-
169	Winona	22-169-
171	Wright	22-171-
173	Yellow Medicine	22-173-

County names are the US Census names for these codes. The API standard does not promise the two match, so we checked them against state well records. Across 35 states, where this table names a county it matched the one the agency recorded on 85,091 of 85,100 wells. Offshore state and federal waters use their own pseudo-county codes, which are not listed here.

Finding the well itself

The API number stops at the county. It does not hold the well's coordinates, lease, survey section or operator. Those sit in the well record, which you find by searching the full number in the state agency's system. Search it at the Minnesota oil and gas regulator.

Frequently asked questions

What is the API state code for Minnesota?

22. API state codes run alphabetically from 01 for Alabama to 49 for Wyoming, then 50 for Alaska and 51 for Hawaii. They are not the Census FIPS state codes, which is a common source of wrong lookups.

How do I find the county from a Minnesota API number?

Read digits three to five and find them in the table on this page. In 22-001-12345, the county code is 001, which is Aitkin County. If the code is missing from the table, it is usually an offshore area rather than an onshore county.

Does a Minnesota API number give the well's exact location?

No. The number stops at the county. Coordinates, the lease and the survey location are in the well record held by the state agency, which you search with the full API number.

State codes: American Petroleum Institute Bulletin D12A well numbering standard. County names: US Census county FIPS names, checked against state well records. Reference generated 2026-09-24.

How to cite this page

Sources: American Petroleum Institute Bulletin D12A well numbering standard; US Census county FIPS codes.

TetraSoft. (2026). Minnesota API county codes. Reference generated 2026-09-24. https://tetrasoftco.com/tools/api-county-codes/minnesota/