Every year, nearby hotels and restaurants can count on a boost. Churches, businesses, and even homeowners offer parking spaces to people who come from throughout the country to go to one of the nation's largest outdoor horse shows, now in its 118th year.
On the surrounding streets, signs shoo away the vehicles bearing horse-show visitors with threats of towing.
As usual, members of St. John's, on Berkley Road, sat on folding chairs under a tent selling spaces. The volunteers sign up for shifts through the 11 days of the show. The parking fees go toward the church's youth program and a charity of the kids' choice.
Visitors to the horse show who park at St. John's contribute more than $10,000 each year, the volunteers said.
"They like paying their money and knowing it's going to help someone else," said Nancy Higgins, 56, who has been a member of the church for about 12 years.
Nearby, Ella's American Bistro in Wayne was relatively quiet around lunchtime, but Jane Lachat, the restaurant's event coordinator, said she expected business to pick up in the later afternoon and evening.
The restaurant is normally closed on Sundays, but it will be open every day during the horse show.
Rooms at Extended Stay America on East Swedesford Road in Malvern were sold out for the first night of the show. Spots are limited during the rest of it.
Inside the grounds, the wind mixed the smells of French fries and funnel cake from the carnival side, with the less savory smells coming from the arenas and stables on the horse-show side.
Before the rain started pouring in the late afternoon, Adele Sands, 53, and her daughter Emma, 19, from Hopkinton, Mass., braved the threat of thunderstorms to travel to Devon to watch riders compete in the show. "We were going to come and stand in the rain if we had to," Adele Sands said.
They didn't know anyone competing in the show, but Emma has been riding since she was 3 years old. Adele has been coming to the Devon Horse Show since she was in kindergarten.
Above the Sands family, Carol McKiernan of Rosemont sat in her box with five of her friends, eating lunch. She'll be back every day of the show.
"This is such a part of the fabric of the community," said McKiernan's friend, Marnie Bowen of Villanova.
It's this kind of loyalty that benefits the people who come back year after year to sell their goods. For the past 18 years, Katie Whaley of Paris, Ky., owner of Hats by Katie, has come to the show to sell her big, colorful hats that would give headpieces at the Kentucky Derby a run for their money.
She got into the hat business for personal reasons. "I have a big head and a lot of hair, so hats wouldn't fit," she said. Whaley said the Devon show is her biggest of the year for hat sales. And she has history there. Whaley and both of her parents used to ride at the show.
"Having grown up here, I wouldn't trade it for the world," she said. "I love coming here."
Inquirer staff writer Jenny Kerrigan contributed to this article.