The West Michigan Pike stretches from the Indiana State Line to Mackinaw City.  It includes parts of U-S 31, U-S 12, Red Arrow Highway and Blue Star Highway.

The new heritage route, called the West Michigan Pike, travels  through the historic communities of New Buffalo, St. Joseph, Benton Harbor, South Haven, Saugatuck, Holland, Grand Haven, Muskegon and the Silver Lake Dunes area.

According to the Mlive story,

The West Michigan Pike was originally developed and constructed between 1911 and 1922 as one of the nation's first tourist roads. What was originally meant to bring vacationers from Chicago eventually developed into a hot bed for the tourism industry complete with sand dunes, state parks, resorts and amusement parks.

Also, adding in a quote from David Lorenz, vice president of Travel Michigan,

This route provides a scenic, diverse and interesting way to travel Michigan to create memories. That's the business we're in. So today we will remember those tourism pioneers that really got it all going and today's tourism innovators.

here is a map highlighting the route.

Google Maps