General Motors Corp. confirmed yesteray earlier reports that the large auto manufacturer will build a new Washington regional headquarters in Rockville.

Following a meeting with Montgomery County officials, the Detroit-based company issued a press release providing details on the proposed three-story building adjacent to the Shady Grove Road exit from Interstate 270.

Rockville Mayor William Hanna said he is "delighted" by the decision of GM, first reported last week in The Washington Post. "This is the kind of industry we like to see . . . environmentally-clean, in a campus-like setting," similar to other local and national company research and facilities along 1-270, Hanna added.

General Motors picked the Rockville location - "one of several choice pieces of property available." Hanna said - over land owned by Martin Marietta Corp. in Bethesda and potential sites in Prince George's County and Northern Virginia.

The auto manufacturer will consolidate initially at Rockville some 160 employes of eight divisions and staffs in the Washington-Baltimore area. A GM spokesmen said additional employes may be moved there at a later date.

Construction is planned to start in November on a 54,000-square-foot building, 80 percent of which will be occupied by GM starting in October 1979. The remaining space will be leased at first but will be available for future GM expansion, the company said.

Units involved in the initial move to Rockville will be the regional and zone Chevrolet division offices, AC Delco, GM's fleet section, GMC Truck & Coach, GM's Motors Holding, and area Oldsmobile, Pontiac and Cadillac offices.

GM said it is seeking state backing for construction of its new office under the Maryland Industrial Development Finance Authority (MIDFA). A company spokesman declined to say how much the new area headquarters will cost but Montgomery County officials said the project has a total value of $3 million.

MIDFA is similar to industrial development agencies in states and local jurisdictions around the country, all designed to attract business with reduced financing or taxation costs. Maryland counties must sponsor specific development projects to get back from the state agency.

In the case of GM, Montgomery County's first use of MIDFA aid, the auto company wants to finance construction with tax-exempt bank loans. The initial tax abatement is provided as a carrot by government to attract business and involves no direct cost to [TEXT OMITTED FROM SOURCE]

Mayor Hanna, recently elected to a third two-year term on a platform that emphasized Rockville's status as an "all-American city" (a designation won in a contest run by the National Municipal League), said yesterday that negotiations currently are in progress with other companies that have expressed an interest in his city.

"As a result or because (of the recent honor) we have been engaged in an overall economic development program for the city . . . the I-270 corridor is attractive aesthetically and has great visibility . . . companies want to enhance their image," with the thousands of persons who use the highway.

Hanna declined to identify companies now talking about Rockville sites but said their proposed facilities would be "compatible" with the GM center. "We're not interested in just any development, only things that meet the city's pattern," he added.

One part of the city, with a population of 50,000, that hasn't kept pace with plans for growth is the downtown Town Center, including an ill-fated shopping mall now seeking rejuvination.

A city committee on development of Town Center recently made recommendations to speed up growth there, including improved traffic flow and "integration" of many buildings into a whole complex by use of pedestrian walkways.

Hanna said a major goal is giving the Rockville skyline a "pleasing visual appearance," in three dimensions, for persons approaching the city, the second largest in Maryland.

"We're one of the lucky communities with financial stability . . . it's partly happenstance and party by design, but we can take some credit," Hanna said.

Currently, there are about 6,000 jobs in the city. City revenues jumped 16 percent to $9 million in fiscal 1977, ended last June 30. That created a budget surplus of $507,147. The city also added $2.8 million to its long-term debts ($24.5 million as of last June 30), as a result of closing out urban renewal projects.