| 1 | RK | Rhenus Keolis GmbH & Co. KG | Mainz | D | privat-bahn.de |
| 2 | RK | Rendsburger Kreisbahn | D | TRAFFIC | |
| 3 | RK | Rhenus Keolis GmbH | DE | VKM | |
| 4 | RKA | Air Afrique | ICAO1 | ||
| 5 | RKAB | RENKAS, CRAIG W | SCAC4 | ||
| 6 | RKAL | RECKART LOGISTICS INC. | SCAC4 | ||
| 7 | RKAM | R & KA | SCAC4 | ||
| 8 | RKAP | RED KAP SALES INC | SCAC4 | ||
| 9 | RKB | Rødkærsbro - Kjellerup Banen (Kjellerupbanen) | 1912 - 1924 | DK | jernbanen.dk |
| 10 | RKB | Rødkærsbro - Kjellerup Banen (Kjellerupbanen) | 1912 - 1924 | DK | TRAFFIC |
| 11 | RKBF | ROCKY BEACH FARMS INC | SCAC3 | ||
| 12 | RKBL | ROYAL KENT BUS LINES INC | SCAC3 | ||
| 13 | RKBL | RAKEBY LIMITED | SCAC4 | ||
| 14 | RKBQ | RIVERA, K & B LIQUID LOGISTICS LLC | SCAC4 | ||
| 15 | RKBS | RICKS BACKHOE SERVICE INC | SCAC4 | ||
| 16 | RKC | DAS Airlines | ICAO1 | ||
| 17 | RKCC | ROCKET CITY CHARTER SERVICE INC | SCAC3 | ||
| 18 | RKCE | ROCK CREEK EXPRESS INC | SCAC3 | ||
| 19 | RKCG | RUKY INTERNATIONAL COMPANY | SCAC4 | ||
| 20 | RKCL | RIMROCK COLONY | SCAC4 | ||
| 21 | RKCT | ROCK CREEK TRUCKING | SCAC4 | ||
| 22 | RKCW | RAKOWSKI CARTAGE & WRECKING LTD | SCAC4 | ||
| 23 | RKCX | Knox Kershaw, Inc. | added 1/1984; eliminated 4/1985; 1/1994-7/2005 (not listed) | NAKINA | |
| 24 | RKCX | Royce Kershaw Co., Inc. | eliminated 1/1984 | NAKINA | |
| 25 | RKCX | Knox Kershaw Co., Inc. | added 1/1969; 4/1970-1/1980 | NAKINA | |
| 26 | RKCX | Knox Kershaw Co., Inc. | added 1/69; 4/70-1/80; eliminated 4/85; 1/94-7/2000 | NRHS | |
| 27 | RKCX | *KNOX KERSHAW INC (ROYCE KERSHAW CO., INC.) | PWRC | ||
| 28 | RKCX | Knox Kershaw | RSRV | ||
| 29 | RKCX | KNOX KERSHAW INC | SCAC4 | ||
| 30 | RKCY | RANDOLPH PACKING CO | SCAC4 | ||
| 31 | RKDA | ROCKDALE TRANSPORTATION ENTERPRISES | SCAC4 | ||
| 32 | RKDB | ROCK LEASING INC | SCAC4 | ||
| 33 | RKDC | ROCKSIDE DISTRIBUTION CENTER | SCAC3 | ||
| 34 | RKDC | ROADSTAR TRUCKING INC | SCAC4 | ||
| 35 | RKDF | R K D FARMS | SCAC3 | ||
| 36 | RKDF | RINKER BOAT COMPANY LLC | SCAC4 | ||
| 37 | RKDG | R K D TRUCKING INC | SCAC3 | ||
| 38 | RKDG | ROGERS TRUCKS & EQUIPMENT INC | SCAC4 | ||
| 39 | RKDI | ROCKETT DELIVERY SERVICE | SCAC3 | ||
| 40 | RKDL | RINKER, DALE F | SCAC3 | ||
| 41 | RKEB | RIDDICK ENTERPRISES INC | SCAC4 | ||
| 42 | RKED | ROAD KING ENTERPRISES AND DISTRIBUT | SCAC4 | ||
| 43 | RKEE | R & K EXPRESS INC | SCAC4 | ||
| 44 | RKEF | ROAD KING EXPRESS FREIGHT INC | SCAC4 | ||
| 45 | RKEI | ROCKET EXPRESS INC | SCAC3 | ||
| 46 | RKEN | ROCKET TRANSPORTATION INC | SCAC3 | ||
| 47 | RKEN | RYKER ENTERPRISES INC | SCAC4 | ||
| 48 | RKEP | ROCKET EXPRESS | SCAC3 | ||
| 49 | RKEQ | ROCKEY, M F MOVING COMPANY | SCAC3 | ||
| 50 | RKEQ | ROCKY BAR RANCH | SCAC4 | ||
| 51 | RKER | R K DISTRIBUTING INC | SCAC4 | ||
| 52 | RKES | ROCKET EXPRESS INC | SCAC3 | ||
| 53 | RKES | ROCKIN K ENTERPRISES LLC | SCAC4 | ||
| 54 | RKET | ROCKET TRUCKING | SCAC3 | ||
| 55 | RKEV | RACE KIT EVENT SERVICE INC | SCAC4 | ||
| 56 | RKEY | ROCKFORD, KERRY ENTERPRISES INC | SCAC4 | ||
| 57 | RKFC | ROCKFORD CARRIER INC | SCAC4 | ||
| 58 | RKFI | R K FUELS INC | SCAC4 | ||
| 59 | RKFL | ROCK FALLS FREIGHT & LEASING CORP | SCAC3 | ||
| 60 | RKFM | REMARK FRESH MARKETS | SCAC4 | ||
| 61 | RKFT | RKF TRUCK LINES LTD | SCAC3 | ||
| 62 | RKG | Rockingham R.R. (Co.) | 7/1923-10/1966 | NAKINA | |
| 63 | RKG | Rockingham R.R. Co. | 4/38-10/66 | NRHS | |
| 64 | RKG | ROCKINGHAM RAILROAD CO. | PWRC | ||
| 65 | RKGI | R & K LOGISTICS INC | SCAC4 | ||
| 66 | RKGL | RICE TRUCKING LLC | SCAC4 | ||
| 67 | RKGN | RESOURCES TRUCKING OF CALIFORNIA IN | SCAC3 | ||
| 68 | RKGP | ROCKING R TRANSPORT | SCAC4 | ||
| 69 | RKGQ | RKG CARRIERS INC | SCAC4 | ||
| 70 | RKGT | ROCKING T INC | SCAC4 | ||
| 71 | RKGX | River King Coal | RSRV | ||
| 72 | RKH | Royal Khmer Airlines | IATA: RK | ICAO1 | |
| 73 | RKH | Regionalverkehr Kurhessen GmbH | D | TRAFFIC | |
| 74 | RKHA | ROCK HAULERS INC | SCAC3 | ||
| 75 | RKHA | ROCKET DELIVERY INC | SCAC4 | ||
| 76 | RKHD | RKH INDUSTRIES INC | SCAC4 | ||
| 77 | RKHI | RICH TRUCKING INC | SCAC4 | ||
| 78 | RKHJ | ROCKHILL, H J INC | SCAC3 | ||
| 79 | RKIA | ROCK-IT CARGO USA LLC | SCAC4 | ||
| 80 | RKIB | ROCK-IT CARGO USA LLC | SCAC4 | ||
| 81 | RKIC | ROCK-IT CARGO USA INC | SCAC3 | ||
| 82 | RKIC | ROCK-IT CARGO USA LLC | SCAC4 | ||
| 83 | RKIG | ROYAL KING ENTERPRISE LTD | SCAC4 | ||
| 84 | RKIK | RKI | SCAC4 | ||
| 85 | RKIP | ROCK IMPLEMENT INC | SCAC3 | ||
| 86 | RKIT | RANKIN TRUCKING, INC | SCAC3 | ||
| 87 | RKIW | ROCK-IT CARGO USA LLC | SCAC4 | ||
| 88 | RKKG | ROOKS TRUCKING CO | SCAC4 | ||
| 89 | RKKL | RKT TRUCKING LLC | SCAC4 | ||
| 90 | RKLC | RK LOGISTICS GROUP INC, THE | SCAC4 | ||
| 91 | RKLD | REEDEREI NORD KLAUS E OLDENDORFF LT | SCAC3 | ||
| 92 | RKLE | RICKARD, LEE | SCAC3 | ||
| 93 | RKLG | RK LOGISTICS GROUP INC, THE | SCAC4 | ||
| 94 | RKLI | RKL ENTERPRISES INC | SCAC4 | ||
| 95 | RKLL | ROAD KING LOGISTICS LLC | SCAC4 | ||
| 96 | RKLU | RENTOKIL LTD | SCAC3 | ||
| 97 | RKM | RAK Airways | ICAO1 | ||
| 98 | RKMC | ROKUCHU MARINE CORPORATION | SCAC3 | ||
| 99 | RKMC | ROCKY MOUNTAIN CARGO LLC | SCAC4 | ||
| 100 | RKMD | ROCKY MOUNTAIN DELIVERY & TRANSPORT | SCAC3 |