The Army of the Republic of Pacific Orange or ARPO is the Pacific Orange Self Defense Forces branch responsible for the co-ordination, planning and execution of all land-based operations involving POSDF forces. It is the largest and oldest branch out of all the POSDF arms and thus functions as the nation's primary operational force. In terms of actual military strength, ARPO currently comprises of approximately 25 000 active duty military personnel, deployed at the various military bases throughout the Republic of Pacific Orange and the local region.