| 1601 | MCOU | 4SEAS SHIPPING AND FORWARDING BV | | NL | BIC |
| 1602 | MCOV | MACOM INCORPORATED | | | SCAC4 |
| 1603 | MCOW | MARYLAND CHEMICAL COMPANY | | | SCAC4 |
| 1604 | MCP | Marcopolo Airways | Callsign: Marcopolo, | AFG | AVCODES |
| 1605 | MCP | Marcopolo Airways | | | ICAO1 |
| 1606 | MCPA | MANATEE COUNTY PORT AUTHORITY | | | PWRC |
| 1607 | MCPA | MCCLURE TRANSPORT CORPORATION | | | SCAC4 |
| 1608 | MCPD | MCCAIN PRODUCE INCORPORATED | | | SCAC4 |
| 1609 | MCPF | M C PARCEL DELIVERY INC | | | SCAC4 |
| 1610 | MCPG | MCPHERS | | | SCAC4 |
| 1611 | MCPH | MILLER CONTAINER CORPORATION | | | SCAC4 |
| 1612 | MCPK | MC TRANSPORTATION & MC TRUCKING | | | SCAC4 |
| 1613 | MCPL | MACLEOD, PHILLIP & SONS TRUCKING LT | | | SCAC4 |
| 1614 | MCPO | M C TRANSPORT | | | SCAC4 |
| 1615 | MCPP | MCNIE PROTECTIVE PADDLING GEAR | | | SCAC4 |
| 1616 | MCPR | MCT TRANSPORTATION LLC | | | SCAC4 |
| 1617 | MCPS | MONTGOMERY COUNTY PUBLIC SCHOOLS | | | SCAC4 |
| 1618 | MCPU | SEALAND MAERSK ASIA PTE LTD | | SGP | BIC |
| 1619 | MCPU | MCC Transport Singapore Pte Ltd. | | | RSRV |
| 1620 | MCPU | MCC TRANSPORT SINGAPORE PTE LTD | | | SCAC4 |
| 1621 | MCPX | Solutia Inc. | added 1/1998; 7/2000; eliminated 10/2004; 7/2005 (not listed) | | NAKINA |
| 1622 | MCPX | Monsanto Co. | added 7/1964; 7/1965-1/1994; eliminated 1/1998 | | NAKINA |
| 1623 | MCPX | Monsanto Chemical Co. | added 4/1962; eliminated 7/1964 | | NAKINA |
| 1624 | MCPX | Mandan Creamery & Produce Co. (North American Car Corp.) | 7/1935 | | NAKINA |
| 1625 | MCPX | Mandan Creamery & Produce Co. | 7/1932 | | NAKINA |
| 1626 | MCPX | M.C. Peters Mill Co. | 8/1920-7/1923 | | NAKINA |
| 1627 | MCPX | Monsanto Chemical Co. | added 4/62; eliminated 7/64 | | NRHS |
| 1628 | MCPX | Monsanto Co. | added 7/64; 7/65-1/94; eliminated 1/98 | | NRHS |
| 1629 | MCPX | Solutia Inc. | added 1/98; 7/2000 | | NRHS |
| 1630 | MCPX | *M.C. PETERS MILL CO. | | | PWRC |
| 1631 | MCPX | *MANDAN CREAMERY & PRODUCE CO. | | | PWRC |
| 1632 | MCPX | +SOLUTIA INCORPORATED [(MONX) MONSANTO COMPANY] | | | PWRC |
| 1633 | MCPX | +MICHAELS CORP. [MICHELS PIPELINE CONSTRUCTION, INC.] | | | PWRC |
| 1634 | MCPX | Monsanto | | | RSRV |
| 1635 | MCPX | SOLUTIA INC | | | SCAC4 |
| 1636 | MCPZ | MINNESOTA CORN PROCESSORS | | | PWRC |
| 1637 | MCQA | MCQ HANDLING INC | | | SCAC4 |
| 1638 | MCQC | M C CARRIER INC | | | SCAC4 |
| 1639 | MCQD | MCQUAID TRANSPORTATION INC | | | SCAC4 |
| 1640 | MCQE | MECANIQUE FORESTIERE S G INC | | | SCAC4 |
| 1641 | MCQF | McQUAIDE, W. C | | | SCAC1 |
| 1642 | MCQH | MCQUAKER, HAROLD ENTERPRISES LTD | | | SCAC4 |
| 1643 | MCQO | MESSER CONSTRUCTION | | | SCAC4 |
| 1644 | MCQP | MINILLAS CONTRACTOR CORP | | | SCAC4 |
| 1645 | MCQQ | MKL COMPUTER MEDIA SUPPLIES INC | | | SCAC4 |
| 1646 | MCQT | MACON TRUCKING INC | | | SCAC4 |
| 1647 | MCQW | MILLS CAPITAL EQUIPMENT SALES LTD | | | SCAC4 |
| 1648 | MCR | Monacair-Agusta | Callsign: Monacair, | MC | AVCODES |
| 1649 | MCR | McCloud Ry. Co. | 1/1994-7/2005 | | NAKINA |
| 1650 | MCR | McCloud River Ry. Co. | 1/1975-1/1980 | | NAKINA |
| 1651 | MCR | McCloud River Ry. Co. | 1/75-1/80 | | NRHS |
| 1652 | MCR | McCloud Ry. Co. | 1/94-7/2000 | | NRHS |
| 1653 | MCR | MCCLOUD RAILWAY COMPANY [MCCLOUD RIVER RWY. CO.] | | | PWRC |
| 1654 | MCR | McCloud River Railroad (McCloud Railway) | | | RSRV |
| 1655 | MCR | MCCLOUD RAILWAY COMPANY | | | SCAC4 |
| 1656 | MCR | McCloud River Railway Company | | USA | TRAFFIC |
| 1657 | MCRC | MCR PRINTING AND PACKAGING CORP | | | SCAC4 |
| 1658 | MCRE | MCCARTNEY, KEITH | | | SCAC4 |
| 1659 | MCRF | MEDINA CORTEZ, EFREN | | | SCAC4 |
| 1660 | MCRI | MARSH, CARL R TRUCKING LLC | | | SCAC4 |
| 1661 | MCRJ | MERCER TRANSPORT LLC | | | SCAC4 |
| 1662 | MCRK | MCCRACK | | | SCAC4 |
| 1663 | MCRM | MID CONTINENT MUSEUM | | | PWRC |
| 1664 | MCRM | MCCORMI | | | SCAC4 |
| 1665 | MCRO | MARTINEZ CHAPA, REYNOL | | | SCAC4 |
| 1666 | MCRR | The Monongahela Connecting R.R. Co. | 1/1975-7/2000; eliminated 1/2003; 7/2005 | | NAKINA |
| 1667 | MCRR | The Monongahela Connecting R.R. Co. | 1/75-7/2000 | | NRHS |
| 1668 | MCRR | MONONGAHELA CONNECTING RAILROAD CO. | | | PWRC |
| 1669 | MCRR | Monongahela Connecting Railroad | | | RSRV |
| 1670 | MCRR | MCRORIE, RICKARD B | | | SCAC4 |
| 1671 | MCRR | The Monongahela Connecting R.R. Co. | | USA | TRAFFIC |
| 1672 | MCRS | MACRIS EXPRESS INC | | | SCAC4 |
| 1673 | MCRT | MCLAUGHLIN ROOF TRUSSES LTD | | | SCAC4 |
| 1674 | MCRU | MAERSK A/S | | DK | BIC |
| 1675 | MCRU | A P MOLLER | | | SCAC4 |
| 1676 | MCRV | MARCARE TRUST 1259 | | | SCAC4 |
| 1677 | MCRW | MAINLY CONVERTIBLES | | | SCAC4 |
| 1678 | MCRW | Maine Coast R.R. Corp. | Real: MCRR | USA | TRAFFIC |
| 1679 | MCRX | Marcus Rail Transport, L.L.C. | 7/2000-7/2005 (not listed) | | NAKINA |
| 1680 | MCRX | McCook Rendering Co. | 4/1947 (not listed); 1/1950-10/1957; eliminated 1/1958 | | NAKINA |
| 1681 | MCRX | McCook Rendering Plant | Jan-52 | | NRHS |
| 1682 | MCRX | McCook Rendering Co. | 10/57; eliminated 1/58 | | NRHS |
| 1683 | MCRX | Marcus Rail Transport, L.L.C. | Jul-00 | | NRHS |
| 1684 | MCRX | *MCCOOK RENDERING CO. | | | PWRC |
| 1685 | MCRX | *MORRISON COVE RAILROAD | | | PWRC |
| 1686 | MCRX | +MARCUS RAIL TRANSPORT [MARCUS CORPORATION] | | | PWRC |
| 1687 | MCRX | Marcus Rail Transport | | | RSRV |
| 1688 | MCRX | MARCUS RAIL TRANSPORT LLC | | | SCAC4 |
| 1689 | MCRY | MID CONTINENT RAILWAY | | | PWRC |
| 1690 | MCRY | Mid Continent Railway | | | RSRV |
| 1691 | MCRY | MERCURY COURIER INC | | | SCAC4 |
| 1692 | MCS | Macedonian Airlines | Callsign: Macair, Founded in 1998. Ceased operations in 2003. | GR | AVCODES |
| 1693 | MCS | MCS AeroCarga de Mexico, S.A. de C.V. | IATA: T8, Callsign: Carmex, IATA Prefix: 137, Name changed to TUM AeroCarga de Mexico, S.A. de C.V. w.e.f. 01 August 2018. | MEX | AVCODES |
| 1694 | MCS | TUM AeroCarga de Mexico, S.A. de C.V. | IATA: T8, Callsign: Carmex, IATA Prefix: 137, IATA designator changed to T2*. Name changed from MCS AeroCarga de Mexico, S.A. de C.V. w.e.f. 01 August 2018. | MEX | AVCODES |
| 1695 | MCS | TUM AeroCarga de Mexico, S.A. de C.V. | IATA: T2, Callsign: Carmex, IATA Prefix: 137, IATA designator changed from T8. Name changed from MCS AeroCarga de Mexico, S.A. de C.V. w.e.f. 01 August 2018. | MEX | AVCODES |
| 1696 | MCS | Macedonian Airlines | | | ICAO1 |
| 1697 | MCS | MYERS COACH LINES INC | | | SCAC4 |
| 1698 | MCSA | Moscow, Camden & San Augustine R.R. | 1/1975; added 7/1979; 1/1980; 1/1994; eliminated 1/2000; 7/2000-7/2005; added 10/2005; eliminated 7/2007 | | NAKINA |
| 1699 | MCSA | Moscow, Camden & San Augustine R.R. | 1/75; added 7/79; 1/80; 1/94; eliminated 1/2000; 7/2000 | | NRHS |
| 1700 | MCSA | MOSCOW, CAMDEN & SAN AUGUSTINE RAILROAD | | | PWRC |
