| Abbreviation | Definition |
|---|---|
| NGVD | National Geodetic Vertical Datum |
| NI | Nitrogen Injection |
| NIGI | Neo Ithaca Geological Institute |
| NKP | No Known Place |
| NKV | Northern Katahdin Valley |
| NMIZ | Northern Marginal Ice Zone |
| NMP | New Map Project |
| NMPM | New Mexico Principal Meridian |
| NMR | Non-metallic Mining Reclamation |
| NMSZ | New Madrid Seismic Zone |
| NMT | Norwegian Method of Tunnelling |
| NNTSLD | Name, North, Title, Scale, Legend, Date |
| NOAA | National Oceanic and Atmospheric Administration |
| NOC | National Oceanography Centre |
| NORM | Naturally-Occurring Radioactive Material |
| NPFD | Numata Pumice Flow Deposit |
| NPG | Nonlinear Processes in Geophysics |
| NPGS | Niagara Peninsula Geological Society |
| NRM | Natural Remanent Magnetization |
| NRP | National Reference Point |