The animals trampled on and destroyed the grass at the park.
"When I first heard it, I thought it was kind of odd, crazy. I didn't think they had wild pigs here," said Robert Valenzuela of Eastvale.
Officials say the wild pigs live somewhere down in the Santa Ana River bottom. The animals didn't have to go far to come up to the park and damage the grass. Officials say the pigs haven't hurt anyone yet.
"It's very mysterious. It's frustrating. Certainly, we don't want to use our park funding to have to replace damage from pigs," said Ross Johnson, park maintenance supervisor for the Jurupa Community Services District.
Johnson says it happened a couple of weeks ago, sometime in the middle of the night.
"The pigs are nocturnal in nature, and they're doing what they do," said Johnson.
The California Department of Fish and Wildlife says, "Wild pigs can be very dangerous to people, however they almost always come out at night and the department has never had a reported injury to a person by a wild pig."
They say pigs can be hunted with a proper hunting license and a pig tag. As for how much it's going to cost to clean up, officials say they won't know for sure just yet.
"But it's probably in the neighborhood of $3,000 to $4,000," said Johnson.