Where can I dispose of pea gravel?

I'm getting around to cleaning my backyard. Previous homeowners had dogs. I guess they hated the dogs digging, so they laid a landscaping tarp and dumped about 2 -3 inches on top. I've been slowly pushing it in to piles and am about ready to start loading and hauling it off.

I checked the main street recycling center. I've dumped some broken concrete there before, but their site says they don't allow rocks. Any ideas on who would take this?