Where in the World are Grandpa and Grandma?

We're on our way, Great God, we're on our way!  We're thinking of a state that entered the union on May 29th, 1848.  That made thirty states here in America.  The explorers from France poked around and poked around and found quite an exciting new territory.  There were borders with two of the five Great Lakes.  There were 14000 lakes,  so we're  hopeful they knew how to swim.  The early settlers found hills and valleys and rivers and dells.  Some of the land was agriculturally rich and some was glacially rugged with rocks.  Nowadays this state is a leader in the production of paper, dairy products and cranberries.  An interesting nonsense fact is that many times you may see people of this state wearing large yellow triangles on their heads. What state is this??           P.S.  5,686,986 people live in this state and some of them are among your favorite people!