The Holiday Inn Express Suites in Aberdeen, SD offers a small indoor water play area.

This newer hotel offers an indoor water play area with an adult pool and a toddler pool. The winding waterslide dumps into the adult pool. The wading pool features a large frog kiddie slide and a cascading water fountain.

Although not truly an "indoor water park", this hotel does offer a couple of pool activities for the little ones and a fun slide for the older kids. You may not be able to make a full vacation out of it, but a fun addition to this nice hotel, nonetheless.