| 1801 | HHLX | H and H Locomotive Leasing | RSRV | ||
| 1802 | HHMO | H & H METALS CO | SCAC4 | ||
| 1803 | HHMX | Golden Eagle Petroleum Co. | added 1/1964; eliminated 7/1965 | NAKINA | |
| 1804 | HHMX | Panoma Corp. | 1/1950 (not listed) | NAKINA | |
| 1805 | HHMX | Hagy, Harrington & Marsh | 1/1943-4/1947 | NAKINA | |
| 1806 | HHMX | Golden Eagle Petroleum Co. | eliminated 7/65 | NRHS | |
| 1807 | HHMX | *HAGY, HARRINGTON & MARSH | PWRC | ||
| 1808 | HHMX | *PANOMA CORP. | PWRC | ||
| 1809 | HHMX | *GOLDEN EAGLE PETROLEUM CO. | PWRC | ||
| 1810 | HHN | Hahn Air | IATA: HR | ICAO1 | |
| 1811 | HHNG | HAHN, GEORGE TRUCKING | SCAC4 | ||
| 1812 | HHNI | HONEY HOUSE NATURALS INC | SCAC4 | ||
| 1813 | HHNS | HORIZON (H & S) FREIGHTWAYS INC | SCAC4 | ||
| 1814 | HHNT | HAHN LOGISTICS L L C | SCAC4 | ||
| 1815 | HHO | Houston Helicopters | ICAO1 | ||
| 1816 | HHOG | HEAVY HAULING OF | SCAC4 | ||
| 1817 | HHOI | HURRYIN HOOSIER INC | SCAC4 | ||
| 1818 | HHON | HEAVY HAULERS OF NORTH EAST OHIO LL | SCAC4 | ||
| 1819 | HHOP | H H OPERATIONS INC | SCAC4 | ||
| 1820 | HHOV | Hamburger Omnibus Verein | D | TRAFFIC | |
| 1821 | HHP | Helenia Helicopter Service | ICAO1 | ||
| 1822 | HHPC | HIGH PRESSURE TRANSPORTS LLC | SCAC4 | ||
| 1823 | HHPE | HI HO PETROLEUM CT COKE INC | SCAC4 | ||
| 1824 | HHPI | Heavy Haul Power International GmbH | Erfurt | D | privat-bahn.de |
| 1825 | HHPI | HOOD, H P INC | SCAC4 | ||
| 1826 | HHPI | Heavy Haul Power International | D | TRAFFIC | |
| 1827 | HHPI | Heavy Haul Power International | DE | VKM | |
| 1828 | HHPO | H & H TRANSPORTATION INC | SCAC4 | ||
| 1829 | HHPP | HATCHER PETROLEUM TRANSPORT INC | SCAC4 | ||
| 1830 | HHPW | HERA SHIPPING & TRADING CO LTD | SCAC4 | ||
| 1831 | HHQT | H & H TRANSPORTATION INC | SCAC4 | ||
| 1832 | HHRI | H & H TRUCKING INC | SCAC4 | ||
| 1833 | HHRL | HUDSON HISTORICS LLC | SCAC4 | ||
| 1834 | HHRR | HIGH RANCH & RODEO CO | SCAC4 | ||
| 1835 | HHRS | Hanson & Hall Rail Services Solutions Ltd. | GB | TRAFFIC | |
| 1836 | HHRV | HORST, HARVEY TRUCKING | SCAC4 | ||
| 1837 | HHRX | H.H. Robertson Co. | 8/1920 | NAKINA | |
| 1838 | HHRX | H.H. ROBERTSON CO. | PWRC | ||
| 1839 | HHS | Hi-Jet Helicopter Services | ICAO1 | ||
| 1840 | HHSE | HIGHHOUSE OIL COMPANY INC | SCAC4 | ||
| 1841 | HHSF | HELENS HOMESTYLE FOODS LTD | SCAC4 | ||
| 1842 | HHSG | HOLY HOUSE SHIPPING AB | SCAC4 | ||
| 1843 | HHSH | HARVIES HOTSHOT SERVICE & T | SCAC4 | ||
| 1844 | HHSL | HIGH ST LOGISTICS INC | SCAC4 | ||
| 1845 | HHSO | HARBOR HOUSE SEAFOOD INC | SCAC4 | ||
| 1846 | HHSP | H & H SPECIALTY VEHICLE TRANSPORTAT | SCAC4 | ||
| 1847 | HHTA | HAYES & HAYES TRANSPORTATION | SCAC4 | ||
| 1848 | HHTB | H & H TRUCKING INC | SCAC4 | ||
| 1849 | HHTF | HY-ON-A HILL TROUT FARM | SCAC4 | ||
| 1850 | HHTG | HI HAT TRUCKING | SCAC4 | ||
| 1851 | HHTI | H & H TRANSPORT INC | SCAC4 | ||
| 1852 | HHTJ | H & H TRUCKING INC | SCAC4 | ||
| 1853 | HHTL | H & H TRANSPORTATION LLC | SCAC4 | ||
| 1854 | HHTM | H & H TRUCKING | SCAC4 | ||
| 1855 | HHTN | HOKE, HERBERT TRANSPORTATION INC | SCAC4 | ||
| 1856 | HHTP | HEAVY HAUL TRANSPORT | SCAC4 | ||
| 1857 | HHTQ | HEAVY HAULERS TRUCKING CORP | SCAC4 | ||
| 1858 | HHTR | H&H TRANSPORT, INC. | SCAC1 | ||
| 1859 | HHTT | HICKORY HILL TRANSPORT CO INC | SCAC4 | ||
| 1860 | HHTU | HEINRICH HAMM | SCAC4 | ||
| 1861 | HHTV | H H TRANSPORTATION SERVICES LLC | SCAC4 | ||
| 1862 | HHTY | HERSH , HENRY TRUCKING INC | SCAC4 | ||
| 1863 | HHUC | H & H FREIGHT INC | SCAC4 | ||
| 1864 | HHVE | HOUSER, HARVEY V ENTERPRISES INC | SCAC4 | ||
| 1865 | HHVL | HARRIS HARVESTING LLC | SCAC4 | ||
| 1866 | HHWF | HERITAGE HARDWOOD FLOORS | SCAC4 | ||
| 1867 | HHWI | HARDY, W HENRY INC | SCAC4 | ||
| 1868 | HHWY | HUB HIGHWAY SERVICES | SCAC4 | ||
| 1869 | HHX | Henaghan & Hanlon | 8/1920-7/1923 | NAKINA | |
| 1870 | HHX | HENAGHAN & HANLON | PWRC | ||
| 1871 | HHXR | H & H EXPRESS CO INC | SCAC4 | ||
| 1872 | HHyJ | Höör - Hörby Järnväg | 1882 - 1915 | S | svenska-lok.se |
| 1873 | HI | Holton Inter-Urban Ry. Co. | 8/1920-10/1966 & 1/1975-1/1980; eliminated 4/1986 | NAKINA | |
| 1874 | HI | Holton Inter-Urban Ry. Co. | 4/38-10/66 & 1/75-1/80; eliminated 4/86 | NRHS | |
| 1875 | HI | HOLTON INTERURBAN RY | PWRC | ||
| 1876 | HI | Holton Interurban Railway | RSRV | ||
| 1877 | HI | Hammersley Iron | AUS | TRAFFIC | |
| 1878 | HIA | Canadian Eagle Aviation | ICAO1 | ||
| 1879 | HIAC | HAULCO INC | SCAC4 | ||
| 1880 | HIAR | HAWAII AIR CARGO INC | SCAC4 | ||
| 1881 | HIB | Helibravo Aviacao | ICAO1 | ||
| 1882 | HIBB | HILL, W W INC | SCAC4 | ||
| 1883 | HIBT | HIBA TRANSPORT | SCAC4 | ||
| 1884 | HIC | THE HIGH IRON CO.INC. | PWRC | ||
| 1885 | HICA | HI C TRANSPORTATION | SCAC4 | ||
| 1886 | HICC | HIGH TRACK LLC | SCAC4 | ||
| 1887 | HICI | HIGH POINT EQUIPMENT LTD | SCAC4 | ||
| 1888 | HICL | HARRINGTON TRUCKING | SCAC4 | ||
| 1889 | HICN | HIE HOLDINGS INC | SCAC4 | ||
| 1890 | HICT | HI C TRANSPORTATION INC | SCAC4 | ||
| 1891 | HICU | HAESAERTS INTERMODAL NV | SCAC4 | ||
| 1892 | HICV | HORIZON INTERNATIONAL CARGO INC | SCAC4 | ||
| 1893 | HICX | HUNTSVILLE INTERNATIONAL INTERMODAL CENTER | PWRC | ||
| 1894 | HICX | Huntsville International Intermodal Center | USA | TRAFFIC | |
| 1895 | HID | Aviacion Ejecutiva De Hildago | ICAO1 | ||
| 1896 | HIDI | HI-DICE TRUCKING | SCAC4 | ||
| 1897 | HIDN | HIDDEN VALLEY TRANSFER INC | SCAC4 | ||
| 1898 | HIDQ | HI-DESERT MOVING & STG | SCAC4 | ||
| 1899 | HIDS | HI-DESERT TRANSFER & STORAGE | SCAC4 | ||
| 1900 | HIDT | HEITER TRUCK LINE INC | SCAC4 |