HathiTrust - HathiTrust is a partnership of academic & research institutions, offering a collection of millions of titles digitized from libraries around the world.
If the copyright has expired, then the full book is downloadable. They have many items on Saginaw, just enter your search term and have fun.
USgennet - list of Saginaw publications in the Library of Michigan
Bavarian Inn Lodge Family Histories - over 350 families who settled Frankenmuth
“Looking Backward” History of Merrill and Jonesfield Townnships
Mid-Michigan Remembers - a project of Delta College - This site has some good history and essays written by Delta College students.
Saginaw County Michigan Photographs - This person has put together a lot of good stuff on RootsWeb free pages and also MiGenWeb.
Pure Saginaw - This is an interesting blog of old and new Saginaw stuff.
Michigan History - Home page for Saginaw - MSU on line student magazine
History of Saginaw County Michigan by James Cooke Mills 1918 - free Google ebook
Weather History of Saginaw since 1921 - who knew!
Saginaw Chippewa Indian Tribe - their website with a brief history
1916 Polk Saginaw City Directory
Archive.org - Internet archive is a non-profit library of millions of free books, music, software, movies and more. Type in Saginaw and see what you find, videos, UFOs, public health regulations, archaeology, genealogy, and much more.