Download U.S. Files

US Historical Counties (1629-2000)

Files GIS Files
+AK/HI
KMZ Files
-AK/HI
KMZ Files
+AK/HI
Full file Not generalized
Generalized .0001 deg. tolerance
Generalized .001 deg. tolerance
Generalized .01 deg. tolerance
Generalized .05 deg. tolerance

US Historical States & Territories (1783-2000)

Files GIS Files
+AK/HI
KMZ Files
-AK/HI
KMZ Files
+AK/HI
Full file Not generalized
Generalized .0001 deg. tolerance
Generalized .001 deg. tolerance
Generalized .01 deg. tolerance
Generalized .05 deg. tolerance

Notes on generalizations

GIS Files

The Full files contain all the detail incorporated in the original state boundary files, and align very closely with the modern county boundaries in Google Earth and ESRI products. However, since the full files are very large, they may not always display rapidly in web applications.

We have therefore created generalized versions of the US historical boundary files. These files contain all of the counties and state/territories included in the full file, along with all of the attribute information. The detail of the boundary lines has been reduced using algorithms incorporated in ESRI software, resulting in a significant reduction in file size. Due to the procedure used, the resulting polygons still fit together exactly at any selected date.

KMZ Files

KMZ files for the US are provided both with and without Alaska & Hawaii. The files shown above as Not Available (N/A) were too large for practical use with Google Earth.

The follow chart shows the approximate scale at which the generalization becomes noticeable on map polygons:

File Scale
Full map N/A
Generalized (.0001 deg. tolerance) 1:25,000 (1 inch = 0.4 mile)
Generalized (.001 deg. tolerance) 1:250,000 (1 inch = 4 miles)
Generalized (.01 deg. tolerance) 1:2,500,000 (1 inch = 39 miles)
Generalized (.05 deg. tolerance) 1:12,500,000 (1 inch = 197 miles)