When Celia Aguilar lifted her red satin gown and swayed to the salsa beat yesterday, thousands in the streets of Adams-Morgan danced with her.

The 96-degree weather did not deter 200,000 people from attending the 17th annual Hispanic Festival, making it the largest ever. Hispanics, the fastest-growing segment of the U.S. population, now number about 250,000 in the Washington area. Yesterday, no one doubted this.

Atop the Salvadoran float in a milelong parade, Aguilar was cheered like a home-town favorite. "Most of us are from Salvador," explained Gladys Gonzalez, a parishioner at Our Lady Queen of the Americas, one of the Catholic churches organizing the event. "But all of us from Spanish-speaking countries like to get together. This is like the Fourth of July for us."

The parade grand marshal, an undocumented and unidentified worker wearing a blue hard hat and jeans, also represented a swelling number of Washington area residents. Although he did not move people to dance, he drew a star's welcome.

As he waved from the back of a Toyota pickup, dozens of women ran up to him as if he were Julio Iglesias or Bruce Willis.

Doffing his hat, he kissed some, hugged others, and pulled the luckiest aboard.

Arlene Gillespie, the director of the D.C. Office on Latino Affairs, said the selection of the grand marshal and the response to him were not without meaning. "The message is that there is a large number of us who are undocumented and we want to stay," she said.

Most people, however, spent more time eating and drinking than thinking about immigration laws.

Norma Small-Warren, a Howard University chemistry professor and native of Panama, said the festival's sounds, sights and smells let immigrants "feel like we've gone home for one afternoon."

Warren wore a pollera, an off-the-shoulder embroidered dress, and a tembleque, a hair ornament of fish scales and pearls.

Asked why -- for just one outdoor party -- so many had spent months making costumes and floats, Warren said: "We are used to having big carnivals. In the United States and Washington, these don't exist. This is our one chance to release what we've suppressed all year."

Hilda Artola, a Nicaraguan who usually has her hands full cooking for her family, stayed up until 3 a.m. Friday making plantains, yucca and pork dishes for 1,500 people.

She served food from one of the 200 kiosks along 18th Street and Columbia Road NW, which were closed to traffic. More than 40 bands were scheduled to play throughout the day, and many booths offered handmade crafts.

The Mexican float, in the Aztec motif, carried warriors who wore footlong peacock plumes. Peruvians transformed a car into a moving mountain on which llamas grazed.

By midafternoon, Brian Bevon had sold 200 gallons of Del's frozen lemonade. And Jaime Stamp had filled so many snowcones that he had shaved an entire 360-pound block of ice and was almost finished with a second.

Despite the mounds of meats grilling on open flames, icy drinks were clearly yesterday's hottest-selling item. One sign enticed the thirsty: "Cheerfully chilled: The coldest sodas on the block."

Armando Soza, a Red Cross volunteer, gave people a cold blast even if they did not ask for it. Soza walked up and down Columbia Road spraying water bottles on the wall of people watching the parade.

As Soza explained, it was not the temperature that worried him: "In Latin America it is very hot; 100 degrees is no problem. But there are too many people here. Too many."

Just how many was unclear. A helicopter hovered over Adams-Morgan, the unofficial port of entry of the area's immigrants, enabling a police photographer to snap photos that will be examined this week to determine the official crowd estimate.

The best guesses yesterday from several of the more than 200 police officers at the event put the figure near 200,000.

Organizers said the first Hispanic festival here in 1970 drew 10,000 people and cost a few thousand dollars. Yesterday's event cost $250,000, including in-kind donations.

Fire officials said three people were rushed to a hospital because of heat-releated problems.

A dozen others who suffered less-serious heat exposure were wrapped in iced towels, said Melvin R. Neils, paramedic supervisor.

"I thought because of the heat, people would stay home," said Gillespie from the grandstand that looked out on a sea of people. "This is unbelievable. It's the biggest community festival."