It happened Tuesday at Church Street Park, where burn marks remain visible on the grass.
Several boxes of fireworks were also left behind.
Police are reminding residents that setting off fireworks is not allowed in Morrisville parks.
"Just use legal ones. Some examples would be sparklers, the little smoke bomb that let off whiter colored smoke," said Morrisville PD Lt. Kent Powell. "If you're going to use them, use the legal ones, and obviously, make sure that you're looking at your local ordinances, like the towns you're not allowed to use any fireworks, legal or illegal, on any park property or greenways."
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As a reminder, Morrisville Police said people should be aware that certain fireworks are illegal to sell or have in North Carolina. These include firecrackers, ground spinners, bottle rockets, Roman candles, and aerial fireworks.
"There were several burn patterns here in the grass, which really affects the aesthetics, and our grounds guys, they have to come out here and fix those things," said Cindi King of Morrisville Parks and Rec.
Anyone with information about the people responsible is asked to contact the Morrisville Police Department at (919) 463-1600.