 When originally signed around July 1 , 1919 , M @-@ 81 ran from Bay City southeast and east to the <unk> area ; from there it ran south concurrently with M @-@ 31 to the Reese area before running northeasterly to the east of Cass City to M @-@ 53 . By 1921 , the eastern end was extended <unk> from Caro to <unk> along a highway that is now part of M @-@ 24 . In late 1926 , the western end was changed so that M @-@ 81 followed the former M @-@ 31 from Reese into Saginaw and the eastern end was rerouted from Caro northeasterly to the Cass City area . With the exception of the routing through downtown Saginaw , the highway followed the approximate routing of the current highway . 
