> Were the United States government to add a second sub-national set of borders for enumerated purposes such as infrastructure planning, etc., I expect a Consti

> Were the United States government to add a second sub-national set of borders for enumerated purposes such as infrastructure planning, etc., I expect a Constitutional amendment. Those kind of already exist... https://en.wikipedia.org/wiki/Special_district_(United_States) https://en.wikipedia.org/wiki/Special_district_(United_State... Special districts don't normally cross state lines, but they can.