We know the busiest international crossing is the USA/Mexico border, but what are the most frequently crossed borders, within the USA?
My guesses are below. Suggestions and criticism welcome!
New York / New Jersey: Pretty obvious first. This border intersects the largest metro area in the USA, up to a million commuters cross daily between NY and NJ, on bridges, tunnels, trains and ferries.
Pennsylvania / New Jersey: Philadelphia is the next largest city directly bordering another state. Long border also runs through many other populated areas such as Trenton and Easton.
DC / Maryland: I think DC metro area is slightly larger than Philly, but its divided among 3 states (well, 1 is a district), rather than 2, so commuters are split in half.
DC / Virginia: Also in the same metro area. Probably less frequently crossed than DC/Maryland because 1) DC is surrounded by Maryland on 3 sides, but Virginia only one side. 2) This is a river border with only 5 bridges, as opposed to a land border that is crossed by every street. 3)Less Virginians have to commute to DC, as there are more centers of employment in Virginia itself, including Pentagon area, Rosslyn and Tysons.
Kansas / Missouri: Kansas City is not that big, but mostly there’s no river barrier, downtown is right next to state line, and the metro area is almost evenly split by the border, unlike most examples where one side clearly dominates.
Ohio / Kentucky: Cincinnati is located right across the Ohio river from Covington and Newport, Kentucky. Cincinnati’s main airport (CVG) is in Kentucky.
Oregon / Washington: Larger than both Kansas City and Cincinnati, but downtown Portland is pretty far from Washington, and the Columbia river is spanned by only a few bridges. I might have underestimated the number of shoppers from WA shopping in OR to avoid sales tax.
