Michigan County War Records, 1917-1919 was a census taken of men serving in the U.S. forces during WWI. The original records, housed at the Archives of Michigan in Lansing, were microfilmed by the Family History Center in 1996 and consist of 266 reels of microfilm.
The Van Buren District Library (VBDL) has recently added to its microfilm indefinite loan collection all of the card index records for the Michigan counties of: Allegan, Berrien, Cass, Kalamazoo, St. Joseph & Van Buren, consisting of 19 reels.
According to Michigan Genealogy : sources & resources, by Carol McGinnis (2nd ed.), these records were compiled in 1923 when the Daughters of the American Revolution in Michigan, working with county War Preparedness Boards, sponsored a census of WWI veterans. Using the last known address, census forms were mailed out to each veteran. The degree of completeness and return rate of these forms varied.
Questions on the census were divided into three categories, personal, war record & family. Included were places for birth/death information, parents' names and current addresses, occupation before & after the war, spousal information including marriage date & place, and list of children with birth dates. In addition, veterans could provide a complete war record comprised of enter/discharge information, rank & promotions, and transfers.
When properly filled out, these records paint a pretty complete portrait of the individual (sorry, no pictures that I've seen), more thorough that any federal or state population census. The cards are easy to use, being arranged first by county, then alphabetically by the name of the veteran.
The SW Michigan films may be viewed in the Local History Collection of the VBDL, or films for any Michigan county may be ordered for viewing through your local Family History Center. If planning a visit to the Archives of Michigan to view the original records, contact them in advance of your visit to learn about access.