Legality of Cannabis by U.S. Jurisdiction Illinois portalUnited States portalHistory portal This category is for topics specifically related to the year 1851 in the U.S. state of Illinois. 18461847184818491850185118521853185418551856 1800s1810s1820s1830s1840s1850s1860s1870s1880s1890s1900s Subcategories This category has the following 2 subcategories, out of 2 total. / 1851 establishments in Illinois (23 P)E 1851 Illinois elections (1 P)