Reference

North Dakota API county codes

Every North Dakota API well number starts with 33, the state code. The next three digits are the county code, one of the 53 listed below, so a number beginning 33-001 belongs to a well in Adams County.

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

How to read a North Dakota API number

33State: North Dakota
001County: Adams
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 53 North Dakota counties

County code County API numbers start
001 Adams 33-001-
003 Barnes 33-003-
005 Benson 33-005-
007 Billings 33-007-
009 Bottineau 33-009-
011 Bowman 33-011-
013 Burke 33-013-
015 Burleigh 33-015-
017 Cass 33-017-
019 Cavalier 33-019-
021 Dickey 33-021-
023 Divide 33-023-
025 Dunn 33-025-
027 Eddy 33-027-
029 Emmons 33-029-
031 Foster 33-031-
033 Golden Valley 33-033-
035 Grand Forks 33-035-
037 Grant 33-037-
039 Griggs 33-039-
041 Hettinger 33-041-
043 Kidder 33-043-
045 LaMoure 33-045-
047 Logan 33-047-
049 McHenry 33-049-
051 McIntosh 33-051-
053 McKenzie 33-053-
055 McLean 33-055-
057 Mercer 33-057-
059 Morton 33-059-
061 Mountrail 33-061-
063 Nelson 33-063-
065 Oliver 33-065-
067 Pembina 33-067-
069 Pierce 33-069-
071 Ramsey 33-071-
073 Ransom 33-073-
075 Renville 33-075-
077 Richland 33-077-
079 Rolette 33-079-
081 Sargent 33-081-
083 Sheridan 33-083-
085 Sioux 33-085-
087 Slope 33-087-
089 Stark 33-089-
091 Steele 33-091-
093 Stutsman 33-093-
095 Towner 33-095-
097 Traill 33-097-
099 Walsh 33-099-
101 Ward 33-101-
103 Wells 33-103-
105 Williams 33-105-

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. In North Dakota that is the NDIC oil and gas division, run by the North Dakota Industrial Commission, Department of Mineral Resources (NDIC).

Frequently asked questions

What is the API state code for North Dakota?

33. 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 North Dakota API number?

Read digits three to five and find them in the table on this page. In 33-001-12345, the county code is 001, which is Adams County. If the code is missing from the table, it is usually an offshore area rather than an onshore county.

Does a North Dakota 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 .

How to cite this page

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

TetraSoft. (2026). North Dakota API county codes. Reference generated 2026-09-24. https://tetrasoftco.com/tools/api-county-codes/north-dakota/