<P> Controversy over whether Missouri should be admitted as a slave state, resulted in the Missouri Compromise of 1820, which specified that Louisiana Purchase territory north of latitude 36 ° 30', which described most of Missouri's southern boundary, would be organized as free states and territory south of that line would be reserved for organization as slave states . As part of the compromise, the admission of Maine (1820) as a free state was secured to balance Missouri's admission as a slave state (1820). </P> <P> The admission of Texas (1845) and the acquisition of the vast new Mexican Cession territories (1848), after the Mexican--American War, created further North - South conflict . Although the settled portion of Texas was an area rich in cotton plantations and dependent on slave labor, the territory acquired in the Mountain West did not seem hospitable to cotton or slavery . </P> <P> As part of the Compromise of 1850, California was admitted as a free state (1850), without a slave state pair . To avoid creating a free state majority in the Senate, California agreed to send one pro-slavery and one anti-slavery senator to Congress . </P> <P> The difficulty of identifying territory that could be organized into additional slave states stalled the process of opening the western territories to settlement, while slave state politicians sought a solution, with efforts being made to acquire Cuba (see: Ostend Manifesto, 1852) and to annex Nicaragua (see: Walker affair, 1856--57), both to be slave states . </P>

What year did each state become a state