Fort Custer State Recreation area is near Augusta off M96 / Dickman Road, with close access for people from Kalamazoo and Battle Creek.
Fort Custer was created as a military training center during WWI, and was greatly expanded during WWII. It appears to have been farmland before that as it is still crisscrossed with old roads, some of which are paved, and foundations of houses and barns are to be found all over. More recently the north west portion of the military preserve was turned into a state recreation area which has a fantastic network of trails. The military side still sees active training and it's not uncommon to hear automatic weapons fire being practiced.
There are three main Mountain bike / hiking trails; The Red Trail, 8.6 miles long, the Green Trail, 7.0 miles long, and the Blue trail, 4.0 miles long. There is also an extensive equestrian trail system which is also open to hiking, which covers a lot of similar terrain as well as some completely different parts of the park, which has a very different character than the mountain bike trails and is well worth exploring. All of these trails are fair game for running as well as the network of old roads, so Fort Custer can keep one busy for quite a while!
The Red Trail was created by mountain bikers for mountain bikers and starts at the main bike trail head and is a fun collection of uppy downey windy mixture of fields and woods with a number of woopdey sections in and out of trenches finishing up with a loop around the crazy beaver pond and more trenches.
The Green Trail, also created by mountain bikers also starts at the main bike trail head and takes a meandering circumambulation of the very convoluted Eagle Lake. It's a beautiful loop offering nice views of the lake, with about four stream crossings, all but one of which are bridged. The unbridged stream is narrow enough that it can usually be jumped. It's also surprisingly cold even in late summer!
The blue trail which circles Jackson, Whitford and Lawler lakes is made up mostly of pre-mountain bike legacy trails and is best started at the Pick-nick area at Whitford lake, or the boat launch at Jackson Lake. This trail also offers nice views of the lakes and goes right by the Fort Custer cabins. It also has a nifty cut off that goes between the lakes so you can mix it up a bit if you wish. There are also connector trails between this and the Red Trail.
All these trails are inter connected so there are plentiful opportunities to play with connections and directions, enough to keep a hardcore ultra runner busy! They also offer occasional water stops for the dogs with access to streams and lake shores, and there is potable water for the humans at the main mountain bike trail head during the temperate spring, summer and fall months. These trails are mildly hilly with almost continuous ups and downs interspersed with occasional flattish sections, and the occasional technical footing. Michigan State Parks vehicle passport is required for entry.
For more information about Fort Custer you can go to the parks website.
Fort Custer State Recreation Area