Port Alto, TexasPort Alto is an unincorporated community in Calhoun County, Texas, United States. According to the Handbook of Texas, the community had a population of 45 in 2000. It is part of the Victoria, Texas Metropolitan Statistical Area.GeographyPort Alto is located at the intersection of Texas State Highway Spur 159 and Farm to Market Road 307 on the western shore of Carancahua Bay, east of Olivia, southwest of Palacios, and northwest of Port Lavaca in northeastern Calhoun County.EducationPort Alto is served by the Calhoun County Independent School District.