Legality of Cannabis by U.S. Jurisdiction United States portal This category is for Washington, D.C. in the year 1820 18151816181718181819182018211822182318241825 1770s1780s1790s1800s1810s1820s1830s1840s1850s1860s1870s See also: Timeline of Washington, D.C. Subcategories This category has only the following subcategory. / 1820 establishments in Washington, D.C. (5 P)