San Francisco celebrated yesterday as several thousand people jammed the streets to welcome home the 49ers, winners of Super Bowl XVI Sunday in Pontiac, Mich.

"Thank you for an unbelievable welcome," Coach Bill Walsh said from the front of City Hall, where Mayor Dianne Feinstein presented Walsh, 49ers owner Edward DeBartolo Jr. and all players keys to the city.

"I hope it's another 35 years before they win another championship," said one of the policemen trying to control the crowd during the ceremonies.

Police barricades were broken as soon as the 49ers arrived at City Hall, riding in antique automobiles and motorized cable cars that had carried them through downtown streets. Several people were hurt, some by police who rode horses into the surging masses.

Sunday night, celebration of the 49ers' 26-21 victory over the Cincinnati Bengals was filled with drunken violence as celebrants clashed with police, authorities said. Dozens of people were hurt and more than 100 arrested.

In Cincinnati yesterday, thousands of screaming, pennant-waving people, oblivious to the snow and subfreezing temperature, jammed Fountain Square to welcome home the Bengals.

It was a heroes' welcome despite the Bengals' loss. The weather was only a slight inconvenience, compared with the wind chill factor of 59 below zero the day the Bengals defeated the San Diego Chargers in Cincinnati for the American Football Conference championship and the Super Bowl berth.

"This really warms my heart . . . to see all you people here," Coach Forrest Gregg told the crowd, estimated by police at about 3,500.

"We didn't accomplish what we wanted to do . . . ," Gregg said, but the crowd didn't let him finish. "Next year, next year, next year!" it chanted.

The crowd cheered loudly when offensive captain Archie Griffin said, "We only got a taste of the Super Bowl this time. Next year, we're going to get a mouthful at Pasadena."