Owner: Platinum Holdings, LLC

Year opened:2002

Size: 25,000 square feet

Staff:50, peak season

Grand Harbor Resort in Dubuque, Iowa, has 194 rooms with a 25,000-square-foot indoor waterpark, themed for the nearby Mississippi River. Waterpark features include slides, a giant play structure, a lazy river, two activity pools and two hot tubs. There’s also an arcade and a Tony Roma’s restaurant on site, and the hotel is connected to a 120,000-square-foot convention center, which it operates for the city. Every Friday and Saturday the waterpark hosts Splash Bash, featuring a live, interactive DJ and poolside games, plus activities in the WaterSquirts Kids Club room.