NATIONAL CITY, Ill. (AP) _ The National Hotel, where St. Louis debutantes wore their finest frocks and cattlemen washed off stockyard dust, will soon fall to the wrecking ball after 115 years, its owners said Wednesday.

''Good business people do what they have to do. It's a matter of economics,'' said Beulah Penry, vice president of the National Stockyards, which owns the southern Illinois hotel.

''The income we get barely gets the weeds cut,'' she said.

The three-story, 100-room hotel stopped admitting guests last September; a bar, restaurant and music store still in the building will have to relocate by June 30, Mrs. Penry said.

The stockyards, she said, is taking bids for the demolition job.

The old hotel is a casualty of changing times.

Truckers still drop off cattle, hogs and sheep at the yards, but they no longer spend the night, Mrs. Penry said.

''In the old days, the livestock shipper traveled a couple hundred miles. They would come in at 7 o'clock, get supper and a room. The next day they would see their livestock sold, pick up a check and go home,'' she recalled.

''But today we have huge interchanges and new highways and it doesn't take as long. Now, they're here in a couple hours, sell their livestock and they're home by noon.

''The days of the overnight shipper are gone,'' Mrs. Penry said, and with them the income the hotel needed to survive.

Last month, hotel fixtures and century-old iron beds were auctioned, along with an elevator installed after it was displayed at the World's Fair in St. Louis in 1904, Mrs. Penry said.

In the hotel's heyday, young Missouri women crossed the Mississippi River to dance in its spacious ballroom. When the stockyards were home to the world's largest mule markets, European traders often reserved rooms.