Reference

Arkansas API county codes

Every Arkansas API well number starts with 03, the state code. The next three digits are the county code, one of the 75 listed below, so a number beginning 03-001 belongs to a well in Arkansas County.

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

How to read a Arkansas API number

03State: Arkansas
001County: Arkansas
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 75 Arkansas counties

County code County API numbers start
001 Arkansas 03-001-
003 Ashley 03-003-
005 Baxter 03-005-
007 Benton 03-007-
009 Boone 03-009-
011 Bradley 03-011-
013 Calhoun 03-013-
015 Carroll 03-015-
017 Chicot 03-017-
019 Clark 03-019-
021 Clay 03-021-
023 Cleburne 03-023-
025 Cleveland 03-025-
027 Columbia 03-027-
029 Conway 03-029-
031 Craighead 03-031-
033 Crawford 03-033-
035 Crittenden 03-035-
037 Cross 03-037-
039 Dallas 03-039-
041 Desha 03-041-
043 Drew 03-043-
045 Faulkner 03-045-
047 Franklin 03-047-
049 Fulton 03-049-
051 Garland 03-051-
053 Grant 03-053-
055 Greene 03-055-
057 Hempstead 03-057-
059 Hot Spring 03-059-
061 Howard 03-061-
063 Independence 03-063-
065 Izard 03-065-
067 Jackson 03-067-
069 Jefferson 03-069-
071 Johnson 03-071-
073 Lafayette 03-073-
075 Lawrence 03-075-
077 Lee 03-077-
079 Lincoln 03-079-
081 Little River 03-081-
083 Logan 03-083-
085 Lonoke 03-085-
087 Madison 03-087-
089 Marion 03-089-
091 Miller 03-091-
093 Mississippi 03-093-
095 Monroe 03-095-
097 Montgomery 03-097-
099 Nevada 03-099-
101 Newton 03-101-
103 Ouachita 03-103-
105 Perry 03-105-
107 Phillips 03-107-
109 Pike 03-109-
111 Poinsett 03-111-
113 Polk 03-113-
115 Pope 03-115-
117 Prairie 03-117-
119 Pulaski 03-119-
121 Randolph 03-121-
123 St. Francis 03-123-
125 Saline 03-125-
127 Scott 03-127-
129 Searcy 03-129-
131 Sebastian 03-131-
133 Sevier 03-133-
135 Sharp 03-135-
137 Stone 03-137-
139 Union 03-139-
141 Van Buren 03-141-
143 Washington 03-143-
145 White 03-145-
147 Woodruff 03-147-
149 Yell 03-149-

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 Arkansas oil and gas regulator.

Frequently asked questions

What is the API state code for Arkansas?

03. 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 Arkansas API number?

Read digits three to five and find them in the table on this page. In 03-001-12345, the county code is 001, which is Arkansas County. If the code is missing from the table, it is usually an offshore area rather than an onshore county.

Does a Arkansas 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). Arkansas API county codes. Reference generated 2026-09-24. https://tetrasoftco.com/tools/api-county-codes/arkansas/