If, like me, you’ve ever wondered where some of the Pittsburgh region’s odder town boundary lines came from…

“Here is a town dependent on one of the great industries of America, which has profited by brilliant invention, by organizing genius, by a national policy of tariff protection. It was studied at the close of one of the longest periods of prosperity known by our generation. What has that prosperity brought to the rank and file of the people whose waking hours are put into the industry?”

…Around the turn of the [20th] century, creative political gerrymandering carved wealthy supervisory and professional enclaves that garnered the taxes paid by industrial properties, leaving the more densely populated working-class districts with school and borough taxes that were substantially higher…. The Borough of Edgewood, for example, was created to include all but the front gate of the Union Switch & Signal under its taxing authority, while Swissvale, where most of its blue collar employees lived, got very little tax benefit from the facility. A similar situation existed between Homestead and Munhall…. The burden on the working poor was accentuated by the fact, common to all the industrial towns, that while mill property was assessed at thirty percent of its value, residential property was assessed at eighty percent of market value.

— Charles McCollester, The Point of Pittsburgh, quoting Paul Kellogg, Director of the Pittsburgh Survey, Editor’s Foreword to Homestead: the households of a mill town

A map of Edgar Thomson Works, greatest and last of the Mon Valley's integrated steel mills, with the boundaries of the boroughs of Braddock and North Braddock overlaid.
This coiled mass of rail lines is Carnegie’s Edgar Thomson Works, built 1873, both one of the earliest and the last of the Mon Valley’s great integrated steel mills. The red box marks the Borough of North Braddock, incorporated 1897 to prevent the mill from being annexed to the fledgling East Pittsburgh, just off the map to the east. Only the westernmost thousand feet (or less) of the plant is actually in Braddock Borough, the town most associated with it.