Chain O'Lakes State Park near Spring Grove in far northeastern Illinois is a network of lakes and marshes along the Fox River. It is one of the most popular boating and fishing destinations in the Chicago region. Boaters can travel between the connected lakes, and the park also offers trails for hiking, biking and horseback riding. Campgrounds make it easy to turn a day trip into a weekend, and the wetlands support many birds and other wildlife. There is no vehicle entry fee, and camping fees vary by site, from $8 to $45 per night. Summer weekends are busy on the water, so consider a weekday visit for a quieter experience.