id author title date pages extension mime words sentences flesch summary cache txt en-wikipedia-org-7216 Territorial evolution of the United States - Wikipedia .html text/html 27411 3157 75 The Oregon Country gave the United States access to the Pacific Ocean, though it was shared for a time with the United Kingdom.[1] The annexation of the Republic of Texas in 1845 led directly to the Mexican–American War, after which the victorious United States obtained the northern half of Mexico's territory, including what was quickly made the state of California.[2] However, as the development of the country moved west, the question of slavery became more important, with vigorous debate over whether the new territories would allow slavery and events such as the Missouri Compromise and Bleeding Kansas. The Congress of the United States moved to Washington in the District of Columbia, now built and ready to be the capital.[24] This was two weeks before the December 1 date established in the Residence Act; President John Adams urged Congress to move early in hopes of securing enough Southern votes to be re-elected, though this failed.[97] ./cache/en-wikipedia-org-7216.html ./txt/en-wikipedia-org-7216.txt