On 24 August 1915 , the regiment moved to Calexico , California to strengthen the border and defend against raids by the bandito , Pancho Villa .
Moving to Southern California , the 1st Cavalry garrisoned San Ysidro in response to growing tensions south of the border in Mexico .
On 24 August 1915 , the regiment moved to Calexico , Southern California to strengthen the border and defend against raids by the bandito , Pancho Villa .
Moving to Southern California , the 1st Cavalry garrisoned San Ysidro in response to growing tensions south of the border in Mexico .