US expansion through post offices

‘This visualization shows how formal US territorial control expanded in North America from 1700 to 1900, as seen through changes in the spatial distribution of post offices.

‘There are a few caveats: the USPS post office data is a constant work in progress, so there are likely many offices that aren’t shown on this map. About 10% of the placenames in the USPS data failed to find any coordinate matches, so those don’t show up. Finally, the USPS data includes closing dates for many offices, but these aren’t represented on the map, which might give a false sense of density in some areas.

‘Still, I think the results are pretty interesting. I’m no historian, but here are a few interesting patterns I’ve noticed aside from general westward expansion:

’1776 – Several new post offices crop up along the east coast after the Revolution.
1846 – Rash of openings in Texas after statehood and the end of the Mexican-American War.
1848 – First offices established on the west coast, with lots of activity afterwards, likely due to gold rushes and CA statehood.
1851 – New Mexico and Utah start to see some activity as they become territories.
1860s – No activity in the South during the Civil War; also an interesting sweep across the Great Plains.
1870s – Distinct traces along railroads in Nebraska and Kansas.
1890s – Oklahoma lights up due to several land rushes.’

- Derek Watkins

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Thank you to Derek Watkins