Castleford is a city in Twin Falls County, Idaho, United States.

It is part of the Twin Falls, Idaho Micropolitan Statistical Area.

Castleford is located on the west bank of Salmon Falls Creek.

According to the United States Census Bureau, the city has a total area of 0.09 square miles (0.23 km2), all of it land.

37.8% of all households were made up of individuals, and 14.5% had someone living alone who was 65 years of age or older.

About 32.7% of families and 35.1% of the population were below the poverty line, including 48.8% of those under the age of eighteen and 38.2% of those 65 or over.