National Industry Definition
The most specific six-digit tier in the U.S. NAICS hierarchy, tailored to reflect specialized U.S. industrial practices.
Related Guides & Tools
- SBA Size Standards Guide — Legal rules of small business classification.
- Federal Contracting Identifiers Guide — Overview of CAGE, DUNS, and Unique Entity IDs.
- SIC ↔ NAICS Concordance Crosswalk — Search and map old SIC codes to modern formats.