Where do we dump charcoal after use

Multiple "charcoal only" disposal bins located throughout the park. There should be one relatively close to every grill.

There are many charcoal dumpsters throughout the park but the easiest one is near the park office

There charcoal dumpster next to the playground also located around the campsites

There are charcoal bin's in different areas of the park

I don't know specifically, but there's an office just past the front entrance inside the park where you can ask.