Eldon is a city in Wapello County, Iowa, United States. The population was 783 at the time of the 2020 census. It is the home of the small Carpenter Gothic style house that served as the backdrop for Grant Wood's 1930 painting, American Gothic.

Eldon got its start in the year 1870, following construction of the Keokuk and Des Moines Railway through the territory. It was incorporated in 1872.

Roseanne Barr and Tom Arnold, who was born in nearby Ottumwa, operated Roseanne and Tom's Big Food Diner in Eldon from 1993 to 1995.

Eldon is also the home of the Wapello County Fair which began in 1868.

Eldon is located in the southeast corner of Wapello County eleven miles southeast of Ottumwa on the northeast bank of the Des Moines River across the river from the Soap creek confluence. Iowa Highway 16 passes through the community. The Eldon Water Management Area is across the river in adjacent Davis County two miles to the southwest along Soap Creek.

According to the United States Census Bureau, the city has a total area of 1.12 square miles (2.90 km²), of which 1.11 square miles (2.87 km²) is land and 0.01 square miles (0.03 km²; 2.59 ha) is water.

Eldon is served by the Cardinal Community School District which has its campus 2.5 miles north of the town in rural Wapello County.

Eldon is consolidated with the towns of Agency, Batavia, and the unincorporated communities of Selma and Bladensburg within the Cardinal Community School District.