There are 5 US Post Offices in Ida County serving a total of 6,983 residents equating to 1,397 residents per post office. It's estimated that approximately 11,146 packages are handled across the 5 county post offices annually. Ida County is a county located in the U.S. state of Iowa. As of the 2010 census, the population was 7,089. The county seat is Ida Grove. The county was formed on January 15, 1851. It was probably named after Ida Smith, the first child of European immigrants to be born in this region.