Sandy D. Since she lived in Ann Arbor from about 1919 to 1933, it's pretty much based on it (just as "A Tree Grows in Brooklyn" is based on her childhood in the Williamsburg and Greenpoint neighborhoods of Brooklyn).
Susan It is in a university town on a river, near a big automobile manufacturing city, and even closer to a smaller blue collar town, and south of the part of the state that has lots of lakes. So it's not Madison, which has lakes of its own and not a river. And it's not any place in Minnesota, because Minnesota is the place Henry goes to. But the school colors seem to be blue and white, not blue and gold. My guess is that it's a made up place.
Ruth It's not called Ann Arbor, though it sounds as if much of the book matches the author's life. I thought it was poorly written and pretty "hokey." Guess I'll have to read A Tree Grows in Brooklyn to see if she really can write.