The correct address for Miller Riverview Park Campground is 2439 Riverview Park Rd. or 1851 Admiral Sheehy Drive depending on your map software.
Not on Marina Drive.
The current map location symbol is the marina.
We wasted about half an hour trying to find someone who knew anything about a campground on the island as the "office" said the campground was closed.
A Google search for "dubuque park campgrounds" gives a Marina and RV park on Marina Dr. but this site is closed.