Harrisburg Pennsylvania
It’s Harrisburg, Pennsylvania. The river is lined up to where either end of it can access the NATO and Soviet Border. There is plenty of flat land, but also many small hills and variations in terrain. The river is wide and deep, with some resources on river islands.
There is power near each customs house- 2 large, 1 medium on the West border, 2 large on the south border, and 2 two large, 1 medium on the east border.
Map data is from https://heightmap.skydark.pl/beta/