Maquoketa is a city in Jackson County, Iowa, United States. Located on the Maquoketa River, it is the county seat of Jackson County. U.S. Route 61 adjoins the city, which therefore hosts traffic between Dubuque and the Quad Cities. Iowa Highways 62 and 64 also pass through the city. Maquoketa Caves State Park is located a few miles northwest of Maquoketa. The population was 6,128 at the time of the 2020 census.