Lopeño is a census-designated place in Zapata County, Texas, United States. The population was 174 at the 2010 census. Lopeño is located at 26°42′36″N 99°6′34″W / 26.71000°N 99.10944°W. According to the United States Census Bureau, the CDP has a total area of 0.8 square mile, all land.