When Union Square Partnership hosts its 11th annual grazing event “Harvest in the Square” on September 19, the park will be teeming with foodies: 45 restaurants, paired with wines and sponsors, are expected to draw 1,200 attendees and generate $100,000 for the partnership.

And why not? Union Square today is New York’s central food district. Culinary interests — from the beloved Greenmarket to pioneering restaurants to new stores like Trader Joe’s — dominate the public space that through Manhattan’s history has been home to a revolving list of industries.

Union Square’s current identity as a mecca for epicureans seems to have exploded as of late. But it was the launch of the Greenmarket, which celebrated its 30th anniversary this month, that put the neighborhood on the foodlover’s map.

“Greenmarket was the biggest thing that turned it around. You have a constituency, and it demands certain things — like safety,” the commissioner of the New York City Department of Small Business Services, Robert Walsh, said. Mr. Walsh was known as the “mayor of Union Square” during his tenure as the executive director of USP between 1989 and 1997. USP was formed in 1976 and was the state’s first Business Improvement District.

Then in 1985, another milestone occurred when a 27-year-old Danny Meyer opened his first restaurant, Union Square Café, at 21 E. 16th St. “Twenty years ago people thought Danny taking the name [of the park] was just a little bit nuts. It wasn’t something to hang your hat on — it was known for drug dealers,” Mr. Walsh said.

Not since the days of Lüchows — which opened in 1882 and moved out in 1982 — was the neighborhood known for eats. “Union Square was always a place you sidestepped,” the author of “On the Town in New York” and founding editor of Food Arts magazine, Michael Batterberry, said. “No one who loved food went here. Union Square Café gave it a luster.”

But for Mr. Meyer, the timing was right. “Union Square Café was fortunate to be born at the right time in the right place,” the restaurateur said. “A magical combination of reasonable rents and a built-in audience.”

His opening and the continued success of the Greenmarket coincided with an emerging new American cuisine. During the ’80s, chefs were re-discovering freshness and seasonality. “American chefs began to see how they could take regional cooking and apply chef skill to local ingredients and recipes,” Mr. Batterberry said.

Gradually, more food-related establishments popped up. Union Square Wines opened on the west side of the square in 1996. Mitchell Soodak bought it in 1999; with thousands of people going by each day, the store did a brisk business and made an effort to be part of the community. “A sommelier came running in on his way to work to buy a corkscrew,” the wine director, Jesse Salazar, said. “We just gave it to him, I mean come on we’re not going to charge you for that. We’re neighbors.”

Relationships with local sommeliers created opportunities of cross-promotion. A wine tasting in the store leads to a round of drinks at the bar, a wine dinner leads to a retail sale the next day. They even barter with farmers, a bottle of Chianti for chicken.

These relationships illustrate the intimate and personal view most of the area’s restaurants and retailers share. There’s a sense of community and shared success. Union Square’s status as foodie magnet is a high tide that not only raises all ships, but all rents as well. When Mr. Meyer took over the lease on 16th Street, the cost was $8 a square foot. Today it is between $150 and $200.

Likewise, Union Square Wine & Spirits relocated three weeks ago; the landlord wanted to increase the rent to between $300 and $400 a square foot — from the previous rent of $80 to $100. The landlord bought out the lease’s remaining three years, in effect paying for the new $1.5-million store on Fourth Avenue at 13th Street.

Some of the new gourmet tenants, such as Trader Joe’s and Whole Foods, which are large chains, can absorb the high rents. “When we went and stood on the corner we said ‘Look at all these people!'” the northeast regional president of Whole Foods, Christina Minardi, said. The store sees about 70,000 customers a week, as opposed to 20,000 at its suburban stores. “We wish we had taken the Forever 21 space, too,” Ms. Minardi said.

The most recent arrival is Max Brenner’s Chocolates by the Bald Man on Broadway at 14th Street. Mr. Brenner lived in New York between 1999 and 2001, and he felt Union Square was the location for his American debut. “Chocolate is for everybody, young, old, rich, poor, every culture. It has no boundaries,” Mr. Brenner said. “Union Square is the place where you find everything — a combination of all the different aspects of life.”

It does help, however, that the Union Square shop is the 20th outlet for the international brand. With stores from Singapore to Australia, Mr. Brenner has means to open in prime real estate.

This raises a question for the future: Can Union Square sustain itself as a food district? The evidence is varied. After Union Square Wine & Spirits moved, its space was taken over by a Puma store. Pioneering young restaurateurs can find less expensive space in Brooklyn and Harlem. “It would be really hard to do it now,” Mr. Meyer said. “But there’s a last gasp on 17th Street on a smaller scale.”

Still, the Greenmarket celebrated its 30th birthday this August and is operating at maximum capacity.Whole Foods has a 20-year lease with an option to renew. Union Square Wine & Spirits has a 15-year lease, and Max Brenner about the same. Mr. Meyer continues to reinvest in the square and is the current cochairman of USP.

He’s the only restaurateur in the city with a director of community investment on his corporate staff. In that post is Jenny Dirksen, whose responsibilities include fund raising, volunteer programs, and charitable events. On her agenda: a redesign of the north end of the park, perhaps as a piazza, and renovations of the play-grounds.USP is not about to relinquish its status as tastiest neighborhood and plans to offer a menu of new programs in 2007 like a chocolate walking tour and a month in the spring to celebrate food.

Its gastronomic allure will most likely continue as Mr. Batterberry said: “Union Square has an almost Proustian aura for New Yorkers — even if they have no memory of it — as a visitation of the past.”