| 1301 | MCDR | MILLARS CEDAR POSTS LIMITED | | | SCAC4 |
| 1302 | MCDS | MCD TRANSPORTATION INC | | | SCAC4 |
| 1303 | MCDT | MICHIGAN DEPARTMENT OF TRANSPORTATION | | | PWRC |
| 1304 | MCDT | MCADEN DAIRY TRUCKING INC | | | SCAC4 |
| 1305 | MCDU | MAKHTESHIM DAROM (RAMAT HOVAV), LTD | | | SCAC4 |
| 1306 | MCDW | MCDOUGALL, WALTER INTERNATIONAL LOG | | | SCAC4 |
| 1307 | MCDX | Sunbelt Cement, Inc. | added 7/1991; 1/1994-7/2000; eliminated 10/2002 | | NAKINA |
| 1308 | MCDX | Cementos Mexicanos, S.A. | added 4/1989; eliminated 7/1991 | | NAKINA |
| 1309 | MCDX | Redland Worth Corp. | added 10/1983; eliminated 4/1986 | | NAKINA |
| 1310 | MCDX | McDonough Brothers, Inc. | added 7/1978; 1/1980; eliminated 10/1983 | | NAKINA |
| 1311 | MCDX | McDonough Brothers, Inc. | added 7/78; 1/80; eliminated 10/83 | | NRHS |
| 1312 | MCDX | Redland Worth Corp. | added 10/83; eliminated 4/86 | | NRHS |
| 1313 | MCDX | Cementos Mexicanos, S.A. | added 4/89; eliminated 7/91 | | NRHS |
| 1314 | MCDX | Sunbelt Cement, Inc. | added 7/91; 1/94-7/2000 | | NRHS |
| 1315 | MCDX | *REDLAND WORTH CORP. [MCDONOUGH BROTHERS, INC.] | | | PWRC |
| 1316 | MCDX | *(MELX) SUNBELT CEMENT, INC. [CEMENTOS MEXICANOS, SA] | | | PWRC |
| 1317 | MCDX | Redland Worth Corporation (Sunbelt Cement) | | | RSRV |
| 1318 | MCDY | MIAMI CRATING & DELIVERY | | | SCAC4 |
| 1319 | MCE | Marshall Of Cambridge (Engineering) Ltd. | Callsign: Marshall, | GB | AVCODES |
| 1320 | MCE | Marshall Aerospace | | | ICAO1 |
| 1321 | MCEB | MGJ CORONA TRUCKING | | | SCAC4 |
| 1322 | MCEC | MAVERICK CARRIERS LLC | | | SCAC4 |
| 1323 | MCEG | MATTCO LOGISTICS | | | SCAC4 |
| 1324 | MCEH | MINA INTERNATIONAL GROUP INC | | | SCAC4 |
| 1325 | MCEL | M/V CELINE AG | | | SCAC4 |
| 1326 | MCEP | MNA TRANSPORT INC | | | SCAC4 |
| 1327 | MCEQ | MCCANN EQUIPMENT LTD | | | SCAC4 |
| 1328 | MCER | Massachusetts Central R.R. | added 4/1995; 7/2000-7/2005 | | NAKINA |
| 1329 | MCER | Massachusetts Central | 1/1980-1/1994 | | NAKINA |
| 1330 | MCER | Massachusetts Central | 1/80-1/94 | | NRHS |
| 1331 | MCER | Massachusetts Central R.R. | added 4/95; 7/2000 | | NRHS |
| 1332 | MCER | MASSACHUSETTS CENTRAL RAILROAD CORP. | | | PWRC |
| 1333 | MCER | Massachusetts Central Railroad | | | RSRV |
| 1334 | MCER | Massachusetts Central R.R. | | USA | TRAFFIC |
| 1335 | MCES | MCELHOSE TRUCKING | | | SCAC4 |
| 1336 | MCET | MERCER TRANSPORTATION CO | | | SCAC1 |
| 1337 | MCET | MERCER TRANSPORTATION CO | | | SCAC4 |
| 1338 | MCEU | MERCURY CONTAINER TRADING GMBH | | D | BIC |
| 1339 | MCEU | MASSACHUSETTS CENTRAL RAILROAD CORP. | | | PWRC |
| 1340 | MCEU | Massachusetts Central Railroad | | | RSRV |
| 1341 | MCEW | MCEWAN, K TRUCKING | | | SCAC4 |
| 1342 | MCEX | Michigan Electrochemical Co. | 7/1930 | | NAKINA |
| 1343 | MCEX | Compania Mexicana de Comereio Exterior, S.A. | 4/1947-7/1965; eliminated 10/1965 | | NAKINA |
| 1344 | MCEX | Compania Mexicana de Comereio Exterior, S.A. | 1/52-7/65; eliminated 10/65 | | NRHS |
| 1345 | MCEX | *COMPANIA MEXICANA DE COMEREIO EXTERIOR, SA | | | PWRC |
| 1346 | MCEX | +MIDWEST RAILCAR CAPITAL EQUIPMENT CORP. | | | PWRC |
| 1347 | MCEX | MIDWEST RAILCAR CAPITAL EQUIPMENT C | | | SCAC4 |
| 1348 | MCEX | Midwest Railcar Capital Equipment Corp. | | USA | TRAFFIC |
| 1349 | MCEZ | *MASSACHUSETTS CENTRAL RAILROAD CORP. | | | PWRC |
| 1350 | MCEZ | *MERNA CO-OP ELEVATOR | | | PWRC |
| 1351 | MCEZ | Massachusetts Central Railroad | | | RSRV |
| 1352 | MCEZ | MASSACHU | | | SCAC4 |
| 1353 | MCF | M.A.C. Fotografica | Callsign: Mac Foto, | E | AVCODES |
| 1354 | MCF | MAC Fotografica | | | ICAO1 |
| 1355 | MCFD | MCCAIN FOODS LTD | | | SCAC4 |
| 1356 | MCFE | MCAFEE TRUCKING CO LLC | | | SCAC4 |
| 1357 | MCFG | MCFARLAND TRUCK LINES INC | | | SCAC4 |
| 1358 | MCFH | MUTUAL CARGO FORWARDER LTD | | | SCAC4 |
| 1359 | MCFK | MCFARLAND TRUCKING | | | SCAC4 |
| 1360 | MCFM | MCKAY, FREEMAN ROBERT | | | SCAC4 |
| 1361 | MCFN | MCFERRAN TRUCKING | | | SCAC4 |
| 1362 | MCFO | MCALPIN TRANSPORTATION INC | | | SCAC4 |
| 1363 | MCFP | MCKINNEY, MURRAY ENTERPRISES INC | | | SCAC4 |
| 1364 | MCFQ | M & R TRUCKING INC OF WISCONSIN | | | SCAC4 |
| 1365 | MCFR | M C FREIGHT | | | SCAC4 |
| 1366 | MCFT | MCCAIN FERTILIZERS LTD | | | SCAC4 |
| 1367 | MCFU | STATE ENTERPRISE RAILWAYS OF MOLDOVA | | MD | BIC |
| 1368 | MCFU | STATE ENTERPRISE RAILWAY OF MOLDOVA | | | SCAC4 |
| 1369 | MCFV | MADISON COUNTY FOOD & BEVERAGE CO L | | | SCAC4 |
| 1370 | MCFW | MCC | | | SCAC4 |
| 1371 | MCFX | McCall Farm Chemicals, Inc. | added 7/1954; 7/1954; eliminated 4/1955 | | NAKINA |
| 1372 | MCFX | McCall Farm Chemicals, Inc. | eliminated 4/55 | | NRHS |
| 1373 | MCFX | MCCALL FARM CHEMICALS, INC. | | | PWRC |
| 1374 | MCG | SOS Helikoptern Gotland AB | Callsign: Medicopter, | S | AVCODES |
| 1375 | MCG | SOS Helikoptern Gotland | | | ICAO1 |
| 1376 | MCGA | MIRANDA CIRILO, GUSTAVO ALONSO | | | SCAC4 |
| 1377 | MCGC | MARINE CARGO LINE LLC | | | SCAC4 |
| 1378 | MCGF | MCGOLDRICK FUEL INC | | | SCAC4 |
| 1379 | MCGG | MILLER CONTRACTING GROUP INC | | | SCAC4 |
| 1380 | MCGH | MCCOLLOUGH, STEVEN | | | SCAC4 |
| 1381 | MCGL | MCGILL TRUCKING CO | | | SCAC4 |
| 1382 | MCGM | MCGARITY MOVING & STORAGE | | | SCAC4 |
| 1383 | MCGN | MICHIGAN TRANSPORT INC | | | SCAC4 |
| 1384 | MCGO | MID-CON CARRIERS CORP | | | SCAC4 |
| 1385 | MCGQ | MERCURY CARTAGE LLC | | | SCAC4 |
| 1386 | MCGR | MCGUIRE LUM | | | SCAC4 |
| 1387 | MCGT | MCGINLEY TRANSPORTATION SYSTEMS | | | SCAC4 |
| 1388 | MCGU | MITSUI CHEMICALS, INC. | | J | BIC |
| 1389 | MCGW | MCGRAW SEAFOOD (1995) INC | | | SCAC4 |
| 1390 | MCGX | Mid-Co. Gasoline Co. | 8/1920 | | NAKINA |
| 1391 | MCGX | MID-CO GASOLINE CO. | | | PWRC |
| 1392 | MCGX | *MERCHANTS DESPATCH TRANSPORTATION CORP. | | | PWRC |
| 1393 | MCH | McAlpine Helicopters Ltd. | Callsign: Macline, | GB | AVCODES |
| 1394 | MCH | McAlpine Helicopters Ltd. | Callsign: Macline Hayes, ICAO callsign changed to Macline | GB | AVCODES |
| 1395 | MCH | McAlpine Helicopters | | | ICAO1 |
| 1396 | MCHB | MICHELS CORPORATION | | | SCAC4 |
| 1397 | MCHE | MICHEK TRANSPORTATION LLC | | | SCAC4 |
| 1398 | MCHF | MINCHOFF FUEL OIL INC | | | SCAC4 |
| 1399 | MCHK | M & CH TRUCKING INC | | | SCAC4 |
| 1400 | MCHM | MATCHMAK | | | SCAC4 |
