The Fort Hays reservation occupied a triangular area of approximately . Like other forts on the Great Plains, it was not a true fortification but appeared to be more like a frontier settlement. There was no wall around the post, and the only defensive structure was a blockhouse. The post was designed as a base for supplies and troops who could be dispatched into the field to protect vulnerable people and places when conflict with Plains Indians broke out. Development of the fort continued over time, and, at one point, it included around 45 buildings.