Sidney is a city located in the U.S. state of Iowa. It is within and the county seat of Fremont County. It has a total area of 1.38 square miles at 40°44′50″N 95°38′49″W. The elevation is 1,168 feet above sea level. As of the 2010 census data, it had a total population of 1,138. The population density was 825/sq mi. Estimated per capita income in 2016 was $26,827. It has Zip code 51652.