Here is another cool old map of Michigan. This one from the public domain Picture Map Geography of the United States. Via the Northern Virginia Community College blog.
Interesting to note the cities that were considered worthy of marking in 1959 (i.e. Saginaw merits inclusion but not Ann Arbor.) How things change over 50 years.
Saginaw had a huge manufacturing base. I'm kind of surprised Bay City wasn't listed on there as well.