I'm adding Chicago-area campgrounds to the Chicago Bike Guide to entice new users and to espouse the enjoyment of medium-distance bike camping. The Chicago Bike Guide is available for Android and iOS.
I'm taking a systematic approach to finding all the publicly-owned campgrounds in the area by looking at primary sources.
First, though, I've used Overpass Turbo to create a list of all existing campgrounds in OpenStreetMap. You can see a gist of these places.
The next method is to find out which campgrounds are operated by the county forest preserves, which are usually well-documented on their respective websites. Then I will look at state parks, operated by states' respective Departments of Natural Resources (DNR). Next I will look at national parks and finally commercial campgrounds.
I've so far mapped the campgrounds in two ways, as nodes and as areas. At the Greene Valley forest preserve in DuPage County, for example, I've mapped the 11 individual camp sites (see map), but at Blackwell forest preserve in the same county, I've mapped the area as a single camp site (see map).
Blackwell has over 50 sites in a discrete area and it's more efficient to map them as a single node, while Greene Valley had far fewer sites but scattered over a couple areas.