San Marcos Police Officers' Association PO Box 1436, San Marcos, Texas 78667-1436 Click on NEWS for the latest from the SMPOA | NEWS | Board Members | LINKS | Ask a Cop |Send us E-mail | The San Marcos Police Officers' Association (SMPOA) was formed in 1995 by concerned officers who wanted to develop a labor oriented association to work toward improving benefits and the quality of service ...