When you look at a map of the United States it is very obvious that the states in the east and west were cut by completely different jigsaw patterns. On the east coast we have states that are small with a variety of odd zigzag shapes. West of the Mississippi, the states are noticeably larger and often rectangular in shape. With some exceptions, those borders don’t meander idly, they are straight and even have some 90 degree corners. What happened?
In a word – – – railroads.
When territories were claiming their borders in the early days of colonization, the primary means of moving people and commerce were the rivers. It was critically important to each colony’s economic viability to have access to the many rivers and bays that crisscrossed the east coast. Without river access, a colony or state would have to depend on its neighbors to provide important routes to move its goods for sale.
So early borders were primarily determined by the course of water.
By the time large numbers of settlers moved west, railroads had taken over as the primary means of transportation. Instead of sending goods up and down the rivers, farmers and business owners loaded them on trains to move from town to town. With a lessened importance on access to rivers, it became more logical to draw borders along straight lines.