Why Colorado and Wyoming Have Straight-Line Borders: The Survey System Explained

Colorado and Wyoming share straight, rectangular borders because they were surveyed using the U.S. Public Land Survey System (PLSS), established by the Land Ordinance of 1785.

How It Works

• The PLSS divides land into a grid of townships (6×6 miles) based on principal meridians (north-south) and baselines (east-west).
• State boundaries in the West were often defined by lines of latitude and longitude—not rivers or mountains.
• Colorado (37°N–41°N, 102°W–109°W) and Wyoming (41°N–45°N, 104°W–111°W) are essentially latitude/longitude rectangles.

This system facilitated land sales, settlement, and governance. It's why many western states look like boxes on the map.