The Polynesian Resort in the Wisconsin Dells is widely recognized as the first established indoor water park in the USA.
The 38,000 sq. ft. indoor water park area includes The Temple of the Black Pearl which features two 2-story water slides, Blackbeard's Dark Tunnel Mystery Voyage Lazy River and the Water Factory kiddie interactive play area and slides.
The 4-acre outdoor water park also offers waterslides, lazy river, interactive pirate ship, Mushroom Waterfalls and an interactive kiddie play area.
Although not as large as some of the indoor water park resorts in the Dells, the Polynesian Resort has a lot to offer and may be more suitable for families with younger children.