Horesethief Canyon Park is located on Sycamore Canyon Rd. just north of E. Foothill Blvd. and adjacent to San Dimas Canyon Park.
Residents in the area were warned to keep clear as the bear is considered dangerous, especially when dealing with food.
The bear could be seen next to a wall separating a residence and a pool from the park.
A Sheriff's deputy was on scene to try to corral the bear. It was unclear whether Animal Control personnel was on scene.