Castana is a city in Monona County, Iowa, United States. The population was 107 at the time of the 2020 census.
History
A post office has been in operation at Castana since 1865. Castana was platted in 1886 by the railroad. The name Castana was selected by an early settler who believed it to be a Latin word meaning "chestnuts".
Geography
thumb|left|upright|Aerial photograph of Castana, Iowa, 2012
According to the United States Census Bureau, the city has a total area of , all land. The city is located from Onawa and from Sioux City.
Academic research
The Western Iowa Experimental farm, a part of Iowa State University, is located just outside Castana. There research is carried out in beef cattle, swine, forage and the effects of fertiliser on soya beans and corn.