From memory, approximately 2 to 2-1/2 feet diameter, around a foot to 15 inches deep. Don't take that as absolute gospel, I didn't measure it, this is just my recall! May be over there again shortly as I want to get some better photos (very dark down there when the leaves are on the trees, probably much better for photography on a bright winter's day!). If so, I'll get an accurate measurement for you.