Cascade Lake, located in Hampstead, MD, has something for everyone, from swimming, waterslides, the Spray'n'Playground, Paddleboats (not included in admission cost), to just a relaxing day of Catch & Release Fishing with a picnic.  

Open 7 days a week in season from 10am to 6pm on weekdays and 10am to 7pm on weekends.

http://www.cascadelake.com