Legality of Cannabis by U.S. Jurisdiction Michigan portalUnited States portalHistory portal This category is for topics specifically related to the year 1840 in the U.S. state of Michigan. 18351836183718381839184018411842184318441845 1790s1800s1810s1820s1830s1840s1850s1860s1870s1880s1890s Subcategories This category has the following 2 subcategories, out of 2 total. / 1840 establishments in Michigan (31 P)E 1840 Michigan elections (4 P)