The data schema for US Census Boundaries is included as part of the product delivery file downloaded from PDX. The current schema workbook and earlier versions can also be downloaded using the following links:
US Census Boundaries Data Schema 2025.03 - Latest
US Census Boundaries Data Schema 2024.03 - 2025.03
US Census Boundaries Data Schema 2023.03 - 2024.03
Note: To access earlier versions not listed above, follow this link and use the Version dropdown to select the appropriate release.