About the Original Presidio

History of the original Presidio Real de San Agustín del Tucson

On the warm, humid morning of August 20, 1775, the Tucson Presidio was established by Regular Spanish Army Lt. Colonel Hugo O'Conor. O'Conor, of Irish descent, was Inspector General and had made a name for himself on the frontier of New Spain.  The construction of the fort probably started the following October.  The Tubac garrison and families moved north in late October of 1776 occupying the earthen berms and palisade that was the Tucson fort. The first correspondence was written from Tucson by Col. Juan Bautista de Anza in November of 1776.


This is one of very few existing historic sketches showing the original presidio.  We can see people visiting outside and more people gathered in the small chapel. 



The fort was small and poorly constructed. In 1782, after a large Apache assault, an 8 to 12 ft high adobe wall was constructed that was about 700 ft long on each side.  The post was continually improved until it reached its maximum size of approximately 11 acres. The land enclosed in these walls sat in what is now present day downtown Tucson, approximately inside the streets of Church, Washington, and Congress, and up to the banks of the Santa Cruz River (which was flowing at that time.) 

Tucson was among the largest of the frontier presidios.  Tucson’s torreons (towers) were state of the art, allowing defense along the walls. The square style torreons are found on most post-1772 presidios.

Early Sketch of the Presidio San Agustín del Tucson


An early sketch of the Presidio showing the enclosed space of 11 acres. The sketch was probably made from the top of Sentinel Peak (now "A" Mountain.) From archaeological digs we know this sketch is not accurate.  There were two lookout towers on opposite corners of the structure.



Pavement marker showing the original Presidio wall foundation.



The Presidio remained in use until the Americans entered Tucson in March 1856, and was dismantled and reused soon after. The last standing segment of the wall was torn down in 1918. The location of the original Presidio wall is marked today by a line of "bricks" that demonstrate how extensive the fort was.