Data Documentation

Tabular Data Sources

Documentation for the digital sources of NHGIS tabular data:

Time Series Tables

Time series tables link together comparable statistics from multiple censuses. The documentation describes how time series are constructed; summarizes which topics, years, and areas are covered; and provides a listing of all table sources and notes.

GIS Files

The GIS files are mainly based on the U.S. Census Bureau TIGER/Line files with additional editing and digitization to produce historical boundaries in accordance with several map sources.

Release Log

Two types of releases are documented: updates to the NHGIS website and updates to the NHGIS data (tabular or boundary data).