Henry Barracks Military Reservation was a lifeline for the residents of Cayey from 1901 to 1966, when it was declared excess land and passed to the General Services Administration for decommission. The property consisted of 439.92 acres (). The property was divided into three prominent encampments: the Spanish Camp- Campamento Español (15 acres), Camp Henry or Henry Barracks, the Home of the third Battalion of the 65th Inf. Regiment that consisted of 372 acres, and 67 acres the Cayey Naval Radio Station (67 acres) ). This reservation is situated in the east of the town of Cayey. The Spanish Reservation containing an area of approximately 15 acres, known as Hospital Hill was set apart by Executive Order of June 30, 1903, under an Act of Congress approved on July 7, 1902. The main army post was located in the northern part of the reservation, initially housing the Puerto Rico Volunteer Infantry Regiment.