Answer:
The piece of legislation that played the greatest role in Michigan's Admission was the The compromise of 1820
Step-by-step explanation:
The Northwest ordinance chartered a government for the northwest territories of which Michigan was part of the northwest it provided a method of admitting new states into the union from the region but the compromise of 1820 played the greatest role in admitting it as a free state because the compromise made all western territories north of Missouri' southern border to be admitted as free state on March 3 1820