Hydro is a town in Caddo and Blaine counties in the U.S. state of Oklahoma.

Built near the Choctaw, Oklahoma and Gulf Railroad, the settlement was originally called "Caddo", but when the post office was established in September 1901, the name was changed to "Hydro" in reference to the town's plentiful well water.

[5] Hydro is located near the northwestern corner of Caddo County at an elevation of 1,557 feet (475 m).

The town is located 0.5 miles (0.80 km) north of Interstate 40, with access from Exit 88.

According to the United States Census Bureau, Hydro has a total area of 0.66 square miles (1.7 km2), all land.