Rouse Co., the once-visionary real estate firm that founded the city of Columbia, Md., and revitalized Harborplace in Baltimore, is being acquired for $7.2 billion in cash by General Growth Properties Inc., a Chicago-based owner and manager of shopping malls.

Rouse, which is based in Columbia, has been a mainstay of the Washington-Baltimore business community for half a century and was renowned internationally for its experimentation in urban and suburban development.

In an announcement this morning, General Growth said the total deal is worth $12.6 billion, including the assumption of approximately $5.4 billion of Rouse's existing debt. Rouse shareholders will receive $67.50 in cash per share, General Growth said in a statement.

Ultimately, Rouse will be merged into an unspecified subsidiary of General Growth.

The deal will become effective in the fourth quarter of 2004 if approved by shareholders. Both companies are publicly traded real estate investment trusts.

Rouse owns or has ownership interests in 37 malls, four community centers and six mixed-use projects across the country.

Founded by developer James W. Rouse, who died in 1996, the Rouse company transformed the landscape of the Washington-Baltimore region and the nation starting in the 1960s.

In addition to Columbia and Harborplace, the company built the Las Vegas suburb of Summerlin, the first indoor shopping mall, Faneuil Hall in Boston and the South Street Seaport in New York City. Harborplace and Faneuil Hall are examples of so-called festival marketplaces that combine specialty shops, restaurants and street entertainment in urban settings. One of the company's signature projects, a $1 billion expansion of Rouse's Fashion Show mall in Las Vegas, is scheduled to open this year.

Rouse has moved primarily into office and industrial property, converting itself into a real estate investment trust in 1998.

General Growth, which is also a real estate investment trust, describes itself as the country's second largest shopping center owner, developer and manager of regional shopping malls, with a portfolio of 178 regional malls in 41 states.