Castolón was originally called Santa Elena. The Mexican village of Santa Elena and Santa Elena Crossing are nearby on the border. Probably Leandro Silvas and Cipriano Hernandez were the first settlers in the area.
Farming was developed and Bob Cartledge established La Harmonia with a store here to supply the farmers. When they got a post office the name of Santa Elena was already being used elsewhere so the name Castolón was created. It probably references the nearby peak known as Castellón.
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