Plaza Land Corporation.

The Plaza Land Corporation was established in 1955 among a group of Detroit civic and business leaders for the purpose of acquiring property adjacent to the soon-to-be constructed "Convention Hall and Exhibits Building (ultimately named for Detroit mayor at the time Albert E. Cobo) and acquiring the financing necessary for a new hotel to be built there.

From the description of Plaza Land Corporation records, 1955-1962. (University of Michigan). WorldCat record id: 773609479

The Plaza Land Corporation was established in 1955 among a group of Detroit civic and business leaders for the purpose of acquiring property adjacent to the soon-to-be constructed "Convention Hall and Exhibits Building" (ultimately named for Detroit mayor at the time Albert E. Cobo) and acquiring the financing necessary for a new hotel to be built there. Originally the hotel was estimated to cost $24 million dollars. In 1956, the Plaza Land Corporation first turned to Conrad Hilton and the Hilton organization to own and operate the proposed hotel, which was originally to be named the Pontchartrain Hilton. In 1960, however, after four years of negotiation, the Hilton board of directors refused to ratify the deal. The Plaza Land Corporation sought out other investors and in 1962 successfully negotiated with the Downtown Investment Company, headed by Samuel and Aaron Gershenson, to take over construction and ownership of the proposed hotel. On July 24, 1965, the 264th anniversary of the founding of Detroit, the Hotel Pontchartrain was dedicated. The hotel was built on the site where Cadillac established the first fort in Detroit.

From the guide to the Plaza Land Corporation records, 1955-1962, (Bentley Historical Library, University of Michigan)