Ontario Beach Park is a great place to take the kids to run around, watch a concert in the summer, have a picnic, walk the pier, and just watch the boats sail in and out of the harbor. It is not a good place to go swimming. More time than not they close the lake. They really need to clean it up.
One of the oldest carousels in the country still spins at this lakeside beach, a 0.5-mile ribbon of sand with a long fishing pier to stroll.