Inauguration day is a holiday for most federal and local government employees, except law enforcement and postal workers.

All government agencies and local libraries, as well as the National Archives and Iibrary of Congress, will be closed today, but post offices in all metropolitan area jurisdictions will remain open and mail will be delivered.

Museums under the direction of the Smithsonian Institution and all monument sites will be open to the public. The Washington Monument will be operating on its summer schedule - remaining open from 8 a.m. to midnight through Saturday.

The orientation center at the monument has been reopened to aid visitors and the film, "Washington the Man," will be shown periodically from 10 a.m. to 4 p.m. at the center's 300-seat theater.

Ice skating will be permitted on the rink at 9th Street and Constitution Avenue and - weather permitting - at Constitution Gardens and the Reflecting Pool.

School systems throughout the Washington area have declared the day a holiday, but students will have to return to their classrooms on Friday, except in the District of Columbia and Fairfax County.

In honor of the day, most parking regulations have been suspended in all jurisdictions except Hyattsville, where citizens will still have to feed parking meters. Of course, there is restricted parking in a wide area from the Capitol to the White House.

Garbage will not be picked up today in the District, but collection will take place on Friday. Refuse will be collected today in all of Washington's suburbs.

U.S. District Courts in Washington will be closed, but the U.S. District Court in Alexandria will be open. The D.C. Superior Court will only hold arraignments today for persons arrested last night. General District Courts and Circuit Courts in the suburbs will be in operation except for the Fairfax Circuit Court.

Most retail and department stores in downtown Washington and lower Connecticut Avenue will be closed but stores will remain open in the suburbs, according to the Metropolitan Washington Board of Trade. Most offices in the downtown area also will be closed for the day. Supermarkets will be open during their regular hours.

Liquor can be bought today in all jurisdictions, but banks and savings and loan associations in the District will be closed. Financial institutions in the suburbs will remain open.