The park celebrated its grand opening in July 2004.
In 2006, the park celebrated its 45th Anniversary by adding ten new attractions geared toward families.
The park celebrated their 40th year anniversary in 2009.
The park will celebrate its 50th anniversary at the 2011 Fourth of July party.
On July 15, 2009, the park celebrated its 20 millionth visitor.
With this milestone the park celebrated its 30 year anniversary.
It is expected that another major new attraction will be developed for the 2015 season, when the park will celebrate its 40th anniversary.
The 800,000-acre national park celebrated its 50th anniversary in 1994 and averages roughly 300,000 visitors a year.
On June 15, 2010 the park celebrated its 75th anniversary with a fundraiser and fireworks display.
The park will celebrate the 10th anniversary of its renovation on April 22.
