| 4801 | NPCX | USI Chemicals Co., Division of National Distillers & Chemical Corp. | added 7/87; eliminated 7/88 | | NRHS |
| 4802 | NPCX | Quantum Chemical Corp., USI Division | added 7/88; 1/94; eliminated 4/98 | | NRHS |
| 4803 | NPCX | Equistar Chemicals, LP | added 4/98; 7/2000 | | NRHS |
| 4804 | NPCX | *NATIONAL POLE CO. | | | PWRC |
| 4805 | NPCX | *NATIONAL CAR CO. | | | PWRC |
| 4806 | NPCX | *NATIONAL BEEF PACKING CO. [NATIONAL PACKING CO.] | | | PWRC |
| 4807 | NPCX | +EQUISTAR CHEMICALS, LP [(USIX) QUANTUM CHEMICAL CORPORATION, USI DIV.; ENRON CHEMICAL CO.; NORCHEM, INMC.; NORTHERN PETROCHEMICAL} | | | PWRC |
| 4808 | NPCX | Northern Petrochemical (Equistar Chemicals) | | | RSRV |
| 4809 | NPCX | EQUISTAR CHEMICALS LP | | | SCAC4 |
| 4810 | NPDE | NEELY TRUCKING INC | | | SCAC3 |
| 4811 | NPDF | NEWPARK DRILLING FLUIDS | | | SCAC4 |
| 4812 | NPDG | Neue Pellwormer Dampfschiffahrts GmbH | | D | TRAFFIC |
| 4813 | NPDI | NPDI INC | | | SCAC3 |
| 4814 | NPDN | NORTHERN PLAINS DISTRIBUTING INC | | | SCAC4 |
| 4815 | NPDR | NAPA DRAYAGE | | | SCAC3 |
| 4816 | NPDU | NEPTUNE PACIFIC DIRECT LINE PTE. LTD. | | SGP | BIC |
| 4817 | NPDX | Nickel Plate Refrigerator Despatch | 7/1923-7/1932 | | NAKINA |
| 4818 | NPDX | NICKEL PLATE REFRIGERATOR DESPATCH | | | PWRC |
| 4819 | NPDZ | N. P. DRAIN | | | PWRC |
| 4820 | NPEC | NCD PACKAGE EXPRESS INC | | | SCAC4 |
| 4821 | NPEE | NPE INC | | | SCAC4 |
| 4822 | NPEI | NANAS PETROLEUM INC | | | SCAC3 |
| 4823 | NPEQ | NATIONAL PRIDE EQUIPMENT | | | SCAC4 |
| 4824 | NPET | NPE TRANS | | | SCAC3 |
| 4825 | NPET | NICKEY PETROLEUM | | | SCAC4 |
| 4826 | NPEX | National Petroleum Corp. | 7/1923 | | NAKINA |
| 4827 | NPEX | NATIONAL PETROLEUM CORP. | | | PWRC |
| 4828 | NPFI | NORTHERN PRIDE FREIGHT INC | | | SCAC4 |
| 4829 | NPFL | NORTH PACIFIC FREIGHT LINES INC | | | SCAC3 |
| 4830 | NPFU | BOLUDA LINES S.A | | E | BIC |
| 4831 | NPG | Supernova Airlines LLC | Callsign: Nova, Owned by Nova Poshta. | UA | AVCODES |
| 4832 | NPG | NPG Bau Neuschitzer GmbH & Co KG | | AT | VKM |
| 4833 | NPGC | NORTHWEST PROPANE GAS CO | | | SCAC4 |
| 4834 | NPGI | NELSON PROPANE GAS INC | | | SCAC4 |
| 4835 | NPGS | NONNA PIAS GOURMET SAUCES LTD | | | SCAC4 |
| 4836 | NPGX | NEWPAGE CORP. | | | PWRC |
| 4837 | NPGX | NEWPAGE CORPORATION | | | SCAC4 |
| 4838 | NPHG | NORTHERN PROFESSIONAL HUNTING GUIDE | | | SCAC4 |
| 4839 | NPIC | NOKOTA PACKERS INCORPORATED | | | SCAC4 |
| 4840 | NPID | NORTHSTAR PRODUCE INC | | | SCAC4 |
| 4841 | NPIE | NAPIER SHIPPING COMPANY | | | SCAC3 |
| 4842 | NPIN | NOVELLA PLASTICS INC | | | SCAC4 |
| 4843 | NPIQ | NORTHLAND PALLET INC | | | SCAC4 |
| 4844 | NPIR | NEW SPIRIT SHIPPING INC | | | SCAC4 |
| 4845 | NPIX | Chem-Nuclear Systems, LLC | 7/2000-7/2005 (not listed) | | NAKINA |
| 4846 | NPIX | VECTRA Technologies, Inc. | added 7/1997; eliminated 4/1998 | | NAKINA |
| 4847 | NPIX | Nuclear Packaging, Inc. | added 1/1988; 1/1994; eliminated 4/1994 | | NAKINA |
| 4848 | NPIX | Nuclear Packaging, Inc. | added 1/88; 1/94; eliminated 4/94 | | NRHS |
| 4849 | NPIX | VECTRA Technologies, Inc. | added 7/97; eliminated 4/98 | | NRHS |
| 4850 | NPIX | Chem-Nuclear Systems, LLC | Jul-00 | | NRHS |
| 4851 | NPIX | CHEM-NUCLEAR SYSTEMS LLC [VECTRA TECHNOLOGIES, INC.; NUCLEAR PACKAGING, INC.] | | | PWRC |
| 4852 | NPIX | Chem-Nuclear Systems | | | RSRV |
| 4853 | NPJF | NEEB, P & J FARM | | | SCAC4 |
| 4854 | NPJU | BOLUDA LINES S.A | | E | BIC |
| 4855 | NPJW | NAPPI, JOHN W INC | | | SCAC3 |
| 4856 | NPJW | NEPTUNE TRANSPORTATION INC | | | SCAC4 |
| 4857 | NPKE | NATIONAL PACKERS EXPRESS INC | | | SCAC3 |
| 4858 | NPKE | NATIONAL PACKERS EXPRESS INC | | | SCAC4 |
| 4859 | NPKP | NIPPON KONPO UNYU SOKO CO LTD | | | SCAC4 |
| 4860 | NPKT | NIP & TUCK TRUCKING | | | SCAC4 |
| 4861 | NPKX | NPK-Tex, Inc. | added 7/1980; eliminated 7/1981 | | NAKINA |
| 4862 | NPKX | General American Transportation Corp. | 7/1937-4/1961; eliminated 10/1962 | | NAKINA |
| 4863 | NPKX | The Nuckolls Packing Co. (North American Car Corp.) | 7/1935 | | NAKINA |
| 4864 | NPKX | The Nuckolls Packing Co. | 7/1930-7/1932 | | NAKINA |
| 4865 | NPKX | The Nuckolls Packing Co. (General American Transportation Corp.) | Apr-38 | | NRHS |
| 4866 | NPKX | General American Transportation Corp. | 1/52-4/61 | | NRHS |
| 4867 | NPKX | NPK-Tex, Inc. | added 7/80; eliminated 7/81 | | NRHS |
| 4868 | NPKX | *NUCKOLLS PACKING CO. (GENERAL AMERICAN TRANSPORTATION CORP.) | | | PWRC |
| 4869 | NPKX | *NPK-TEX, INC. | | | PWRC |
| 4870 | NPL | Air Nepal International Pvt. Ltd. | IATA: SZ, Callsign: Air Nepal, IATA Prefix: 855, All of its flights were suspended from 22 December 2005. | NEP | AVCODES |
| 4871 | NPL | Air Nepal International | | | ICAO1 |
| 4872 | NPL | Neopul - Sociedade de Estudos e Construção, S.A. | | PT | VKM |
| 4873 | NPLC | NADEAU, PHILIPPE LOGGING CONTRACTOR | | | SCAC3 |
| 4874 | NPLG | NORTH POINT LOGISTICS INC | | | SCAC4 |
| 4875 | NPLI | NATIONAL PIPELINE CO | | | SCAC3 |
| 4876 | NPLK | NELSON, P L TRUCKING | | | SCAC4 |
| 4877 | NPLP | NRG PETROLEUM LP | | | SCAC4 |
| 4878 | NPLU | SAIGON NEWPORT ONE MEMBER LTD LIABILITY CORP | | VN | BIC |
| 4879 | NPLU | NAURU PACIFIC LINE | | | SCAC3 |
| 4880 | NPLW | NAVIG8 PTE LTD | | | SCAC4 |
| 4881 | NPLX | North Pacific Lumber Co. | added 10/1979; 1/1980; eliminated 1/1981 | | NAKINA |
| 4882 | NPLX | Nickel Plate-Lackawanna Dairy Line | 7/1932 | | NAKINA |
| 4883 | NPLX | Nickel Plate-Lackawanna Dairy Line (New York, Chicago & St. Louis R.R. Co.) | 7/1930 | | NAKINA |
| 4884 | NPLX | Nickel Plate-Lackawanna Dairy Line (Mid-West Despatch Car Co./Atlantic Seaboard Despatch) | 7/1923 | | NAKINA |
| 4885 | NPLX | North Pacific Lumber Co. | 1/80; eliminated 1/81 | | NRHS |
| 4886 | NPLX | *NICKEL PLATE-LACKAWANNA DAIRY LINE | | | PWRC |
| 4887 | NPLX | *NORTH PACIFIC LUMBER CO. | | | PWRC |
| 4888 | NPM | Northern Pacific Ry. Co. | 4/1961-10/1966 | | NAKINA |
| 4889 | NPM | Northern Pacific Ry. Co. | 4/61-10/66 | | NRHS |
| 4890 | NPM | NORTHERN PACIFIC RWY. CO. | | | PWRC |
| 4891 | NPMA | NASSAU PRINTING MACHINERY INC | | | SCAC4 |
| 4892 | NPMB | Næstved - Præstø - Mern Banen (Præstøbanen) | 1900 - 1961 | DK | jernbanen.dk |
| 4893 | NPMB | Næstved - Præstø - Mern Banen (Præstøbanen) | 1900 - 1961 | DK | TRAFFIC |
| 4894 | NPMC | NEPTUNE MARITIME CO OF MONROVIA | | | SCAC3 |
| 4895 | NPME | NEW PENN MOTOR EXPRESS, INC | | | SCAC3 |
| 4896 | NPME | NEW PENN MOTOR EXPRESS, INC | | | SCAC4 |
| 4897 | NPMG | NAGLE/POOR MOVING & STORAGE CO INC | | | SCAC3 |
| 4898 | NPMI | NORTH PACIFIC MARITIME INC | | | SCAC3 |
| 4899 | NPMI | NORTH PACIFIC MARITIME INC | | | SCAC4 |
| 4900 | NPMR | NAVY POINT MARINE INC | | | SCAC4 |
