According to research shared by Chris Hogan, which he reports on in his new book, Everyday Millionaires, of the 10K millionaires he interviewed:
about 60% attended public state colleges
about 8% attended community college
about 9% did not attend college.
The majority did NOT attend prestigious colleges.

Other findings:
- most millionaires did not earn 6-figure salaries,
- most millionaires did not inherit,
- most millionaires are first-generation wealth-builders,
- most millionaires budgeted and saved.
- More info is available at the links in this post.

Related threads/posts:
Where You Go Is Not Who You'll Be (March, 2015)