Eldorado is a village in Preble County, Ohio, United States.

According to the United States Census Bureau, the village has a total area of 0.23 square miles (0.60 km2), all land.

There were 223 housing units at an average density of 969.6 per square mile (374.4/km2).

20.9% of all households were made up of individuals, and 8.1% had someone living alone who was 65 years of age or older.

24.1% of all households were made up of individuals, and 12.3% had someone living alone who was 65 years of age or older.

The National Trail Local School District serves students from Eldorado and surrounding Monroe Township.