I just wanted to say a big thank you to the community and maintainers of Natural Earth. I’ve spent months trying to track down state and province boundaries for countries around the world one-by-one. Once I discovered your Admin1 data set I was able to add support for almost every country in the world very quickly:
http://petewarden.typepad.com/searchbrowser/2010/10/openheatmap-now-supports-states-and-provinces-worldwide.html
Importing the shapefiles went very smoothly and the results were both high-quality and had reasonable file sizes. Keep up the fantastic work, and let me know if there’s anything I can do to spread the word.
@Pete: You’re welcome! Please feed any corrections our way so we can stay current, either in the forum here or using the Corrections tab above. We have an update to roll out for some better naming on 50% of the data in the most populous, largest geography countries. Sometime this fall into winter on timing. Keep up your good work!
I agree, this was not easy to find, and I am so grateful to NaturalEarth. I will certainly be using this data in my site, and I hope to be able to contribute here. I am now looking for UN Region and Subregion shapefiles… any ideas?
@Sean: You’ll want to do a data join from the UN region and subregion codes for each country based on the country name or UN / ISO id. Then dissolve based on the region and subregion codes.
Oh, I’ve done the data join bit, and have the list of countries per UN Region / SubRegion, and the polygons for each. That is not the issue. It is the “dissolve” bit that I am a little fuzzy on (how to get rid of the interior boundaries) 
In QGIS… Vector > Geoprocessing > Dissolve.
.
