Police in the Delaware County town of Brookhaven say the blades affixed to equipment in Eaton Park could have injured children playing in the area.
They said other parks in the town had been checked and were clear, but they will be checked by both patrol and plainclothes officers on every shift.
On their Facebook page, police asked parents to check equipment before letting children play, and said older, unescorted children should be warned as well.
Police credited maintenance personnel for discovering the vandalism. No injuries were reported.
A week ago, authorities in western Illinois found a dozen razor blades glued to playground equipment in a city park in East Moline.