The list is the FIPS codes of Oklahoma counties. All the FIPS codes are starting with 40.
| County | FIPS Code |
| Adair | 40001 |
| Alfalfa | 40003 |
| Atoka | 40005 |
| Beaver | 40007 |
| Beckham | 40009 |
| Blaine | 40011 |
| Bryan | 40013 |
| Caddo | 40015 |
| Canadian | 40017 |
| Carter | 40019 |
| Cherokee | 40021 |
| Choctaw | 40023 |
| Cimarron | 40025 |
| Cleveland | 40027 |
| Coal | 40029 |
| Comanche | 40031 |
| Cotton | 40033 |
| Craig | 40035 |
| Creek | 40037 |
| Custer | 40039 |
| Delaware | 40041 |
| Dewey | 40043 |
| Ellis | 40045 |
| Garfield | 40047 |
| Garvin | 40049 |
| Grady | 40051 |
| Grant | 40053 |
| Greer | 40055 |
| Harmon | 40057 |
| Harper | 40059 |
| Haskell | 40061 |
| Hughes | 40063 |
| Jackson | 40065 |
| Jefferson | 40067 |
| Johnston | 40069 |
| Kay | 40071 |
| Kingfisher | 40073 |
| Kiowa | 40075 |
| Latimer | 40077 |
| Le Flore | 40079 |
| Lincoln | 40081 |
| Logan | 40083 |
| Love | 40085 |
| Major | 40093 |
| Marshall | 40095 |
| Mayes | 40097 |
| McClain | 40087 |
| McCurtain | 40089 |
| McIntosh | 40091 |
| Murray | 40099 |
| Muskogee | 40101 |
| Noble | 40103 |
| Nowata | 40105 |
| Okfuskee | 40107 |
| Oklahoma | 40109 |
| Okmulgee | 40111 |
| Osage | 40113 |
| Ottawa | 40115 |
| Pawnee | 40117 |
| Payne | 40119 |
| Pittsburg | 40121 |
| Pontotoc | 40123 |
| Pottawatomie | 40125 |
| Pushmataha | 40127 |
| Roger Mills | 40129 |
| Rogers | 40131 |
| Seminole | 40133 |
| Sequoyah | 40135 |
| Stephens | 40137 |
| Texas | 40139 |
| Tillman | 40141 |
| Tulsa | 40143 |
| Wagoner | 40145 |
| Washington | 40147 |
| Washita | 40149 |
| Woods | 40151 |
| Woodward | 40153 |
All codes are cited from United States Department of Agriculture [28].