Sunday, May 5, 2013

Online US County Boundary Changes

For those of you who just completed my Internet and Genealogy class, I have an update for your notes.

Knowing US county boundaries on various dates in our ancestors timeline is extremely important. No sense in looking in a particular county for a genealogy record if that county had not been established yet.

So what is a genealogist suppose to do? A free website the Atlas of Historical County Boundaries on the website is the online answer.

The Atlas of Historical County Boundaries is meant to be a resource for people seeking records of past events, and people trying to analyze, interpret and display county-based historical data like returns of elections and censuses, and for people working on state and local history projects. The special interests of those potential users range from history to demography, economics, genealogy, geography, law, and politics. While many of these goals can be achieved using the Atlas' Interactive Maps, the downloadable data can be used with various GIS (Geographic Information Systems) programs to create specialized projects.

A project of the William M. Scholl Center for American History and Culture at The Newberry Library in Chicago, the Atlas of Historical County Boundaries is a powerful historical research and reference tool in electronic form. The Atlas presents in maps and text complete data about the creation and all subsequent changes (dated to the day) in the size, shape, and location of every county in the fifty United States and the District of Columbia. It also includes non-county areas, unsuccessful authorizations for new counties, changes in county names and organization, and the temporary attachments of non-county areas and unorganized counties to fully functioning counties. The principal sources for these data are the most authoritative available: the session laws of the colonies, territories, and states that created and changed the counties.

What makes this Atlas stand out?

Over a dozen features distinguish the volumes and files of this atlas from other compilations.
  1. All boundary changes in states and counties-unrivaled historical and geographic coverage.
  2. Non-county areas-never before compiled or mapped.
  3. Attachments to operational counties (non-county areas and unorganized counties)-never before compiled or mapped.
  4. Separate map or polygon for every different county configuration-clarity and ease of use.
  5. Based on original research in primary sources-unlike most reference works.
  6. Primary sources cited for every change-unmatched documentation.
  7. Information organized by both date and county-unmatched flexibility.
  8. Locator maps for all county maps-show each county's location within its state.
  9. Area (sq. mi.) for each county configuration-available nowhere else.
  10. Polygons available in two formats: shapefiles and KMZ-broad applicability.
  11. Interactive map has many options for background-unmatched convenience.
  12. Supplementary bibliography, chronologies, and commentary-unusually complete and thorough data presentation.
  13. Short and Long metadata documents for each state dataset-convenience and completeness.
You can view this wondeful resource at