DENVER -- Six Flags agreed to sell seven of its parks, including Six Flags Elitch Gardens, for $312 million on Thursday.

Six Flags, Inc., announced it reached agreement to sell three of its water parks and four of it's theme parks to PARC of Jacksonvill, Fla.

The venues involved in the sale are: Six Flags Darien Lake in Buffalo, N.Y.; Six Flags Elitch Gardens in Denver; Frontier City and the White Water Bay water park in Oklahoma City, Okla.; SplashTown in Houston, Texas; Waterworld USA in Concord, Calif.; and Wild Waves and Enchanted Village in Seattle, Wash.

Six Flags is the owner and operator of 27 North American parks, including the seven it plans to sell.

Shares of Six Flags gained 41 cents, or almost 8 percent, to $5.84 in afternoon trading on the New York Stock Exchange after the news.

The sale comes after Six Flags underwent a series of changes in recent years, with Mark Shapiro becoming chief executive of the company in December 2005. His appointment followed a proxy fight led by investor and Washington Redskins owner Daniel Snyder that resulted in the ouster of former CEO Keirian Burke and other executives.

The company said the sale is part of its strategy to reduce debt and enhance its operational and financial flexibility. Combined with the June sale of land underlying its Houston AstroWorld theme park for $77 million, the sale will result in proceeds of $352 million to be used for debt reduction, according to the company.

Six Flags Magic Mountain and the adjacent Hurricane Harbor water park in Valencia, Calif. were not included in the sale.

The deal is expected to close in March, subject to customary closing conditions.

PARC noted that obligations with respect to 2007 season passes and any committed park events, including group bookings and the previously announced Dream Nite promotion, will continue to be fulfilled under the new park ownership.

Six Flags reported last month that 2006 attendance slipped 14 percent from the previous year. In November, the company said third-quarter earnings fell 16 percent to $159.3 million, or $1.08 per share, below Wall Street's expectations. Revenue in that quarter slid 1 percent to $540.7 million.

Although Elitch Gardens will no longer carry the Six Flags brand under the new ownership, any 2007 season passes purchased at the park will continue to be honored at all Six Flags branded parks throughout the 2007 season.

Elitch Gardens moved from northwest Denver to downtown Denver in 1995.