Ryan is a city in Delaware County, Iowa, United States. The population was 350 at the time of the 2020 census. Ryan is located at 42°21′2″…Ryan is a city in Delaware County, Iowa, United States. The population was 350 at the time of the 2020 census. Ryan is located at 42°21′2″N 91°28′59″W / 42.35056°N 91.48306°W. According to the United States Census Bureau, the city has a total area of 0.43 square miles, all land.