| Acronym |
Definition |
| NBIS | National Bridge Inspection Standards |
| NCDOT | North Carolina Department of Transportation |
| NCHRP | National Cooperative Highway Research Program |
| NDDOT | North Dakota Department of Transportation |
| NDOR | Nebraska Department of Roads |
| NDOT | Nevada Department of Transportation |
| NEPA | National Environmental Policy Act |
| NEPE | Nez Perce National Historical Park |
| NF | National Forest |
| NHDOT | New Hampshire Department of Transportation |
| NHL | National Historic Landmark |
| NHS | National Highway System |
| NJDOT | New Jersey Department of Transportation |
| NMSHTD | New Mexico State Highways & Transportation Department |
| NOAA | National Oceanic and Atmospheric Administration |
| NOCA | North Cascades National Park |
| NOI | Notice of Intent |
| NPDES | National Pollutant Discharge Elimination System |
| NPRM | Notice of Proposed Rulemaking |
| NPS | National Park Service |
| NRHP | National Register of Historic Places |
| NTHP | National Trust for Historic Preservation |
| NTP | Notice to Proceed |
| NWAAI | Northwest Archaeological Associates, Inc |
| NWP | Nationwide Permit |
| NWR | National Wildlife Refuge |
| NYSDOT | New York State Department of Transportation |
