The Michigan legislature enacts the “Burns Act” prohibiting “public gatherings of masked men.” The law is carefully drafted to apply almost exclusively to Ku Klux Klan activity.
Apparently, the Ku Klux Klan was fairly active in the Michigan of the 1920s. At the height of its power in the 1920s, the “Invisible Empire” had what Fox called “staggering membership numbers,” exceeding 6 million members nationwide. Although Michigan membership is difficult to pinpoint, Fox cites reports of between 265,000 to 875,000 members. Many prominent businessmen, doctors and lawyers found their way to Klan membership, including Dan F. Gerber, the founder of Gerber Baby Foods.
In Lansing, the Klan was able to muster more than 15,000 members for a march down Michigan Avenue on Labor Day in 1924.
Klan activities in Michigan fizzled out by 1926.
Bill Castanier, “1920s Michigan: Klan Country“, Lansing City Pulse,
Also see Everyday Klansfolk: White Protestant Life and the KKK in 1920s Michigan by Craig Fox. East Lansing : Michigan State University Press,  Also available online to the current MSU community.