The scene resembled a jubilant lawn party, a blend of sport, drink, dining, and mingling, and many attendees Saturday were quick to express their love of the festivities.
"This is one of my favorite days of the year," said Sally Price, wearing a hat she made of pink flowers.
She has attended every year for more than two decades, she said, because "nothing takes precedence over the Radnor Hunt Races."
The races - held at Radnor Hunt, which calls itself the nation's oldest foxhunting organization - began in 1930. They are accredited by the National Steeplechase Association, and one of the afternoon's six races, the National Hunt Cup, had a $50,000 purse.
The event is also a major fund-raiser for the Brandywine Conservancy. This year, according to sponsorship coordinator Kathie Brown, the race attracted about $200,000 worth of sponsorships, and ticket sales and tailgating fees generate additional revenue.
For most of the 20,000 who attended, however, the big draw of the afternoon was the chance to dress up and socialize, sharing food and cocktails with friends and family.
"It's the party," said Chris Thomson, of Malvern. "It's just the races and a good day to get out."
Thomson was standing next to a 1954 Rolls-Royce Silver Dawn owned by his friend Don Rosato, of Chester Springs. The gray car had a table sticking out of the trunk, with champagne and mixed drinks sitting atop the red tablecloth that draped to the ground.
A host of other vintage cars were scattered about a tailgating lot overlooking the track, including a dark-green 1965 AC Cobra Replica, a wood-paneled 1947 Chevrolet Special Deluxe wagon, and a 1958 Ferrari 250 GT.
There was also a themed tailgating competition, and this year's subject was holidays around the world. Those participating in the theme wore costumes, served food, or decorated their areas to represent Cinco de Mayo, Bastille Day, and the Fourth of July.
Tish Moyer, 65, from Chester Springs, hosted a Chinese New Year-themed tailgate and had a giant homemade snake on top of her Mercedes station wagon.
She called the races a great opportunity to catch up with friends.
"You see a lot of friends," she said. "People come through, wander in, have a drink. It's fun."
Matthew McGeever, 27, of West Chester, was serving shrimp cocktail and spinach salad out of the trunk of his 1968 Ferrari 330 GTC.
Because of the event's novelty, he said, "it feels really special." He says he has attended for about 10 years.
"I don't believe I'll ever stop doing it," he said.
Contact Chris Palmer
at email@example.com, 609-217-8305, or on Twitter @cs_palmerr.