The State highway system dates from the Hawes Act (1917), passed to take advantage of the Federal aid, and the Centennial Road Act (1921). The latter outlined the system and provided for the expenditure of a $6o,000,000 bond issue approved by popular vote in 1920. Automobile licence fees and a gasolene tax provide additional funds. Of the total mileage of 8,082 under the highway department, on Dec. 31, 1934, 7,871m. had been surfaced. New surfacing laid during 1934 amounted to 722 miles.
Louisiana Purchase (q.v.) north of the present State of Louisiana was attached to Indiana Territory in 2804, organized as Louisiana Territory in 1805, and the name changed to Missouri in 1812. A legislature with elective lower house was granted in 1812, the upper house was made elective in 1816. In 1818 the legislature petitioned for Statehood and in 1821 Missouri was admitted to the Union as a slave State under the Missouri Compromise (q.v.). The Indians were never a serious problem in Missouri, although the Sac and Fox from the north-east drove the outlying pioneers into blockhouses along the Missouri and upper Missouri during the war of 1812 ; they surrendered their claims in 1815-16.
The population grew slowly until the great influx after 1815 to the new areas along the upper Mississippi and the Boonslick country along the Missouri in the central part of the State. Of the 66,586 total population in 1820, nearly one-half were in these districts. In the succeeding decades the south-east filled in up to the Ozark section, the Missouri valley and the north-east were occupied until the two areas merged; the Platte Purchase in the north-west, annexed in 1837, filled up very quickly. The north central section was settled later, in part from Iowa, while the south-west Ozark border lands, except around Springfield, and the Ozarks proper were sparsely settled even in 1860. Through 1850 the total population increased at the characteristic frontier rate, more than doubling in the '20S and '3os and increasing by three fourths in each of the next two decades, reaching 1,182,012 in 186o. Until 1850 most of the settlers were of the Southern type, from Kentucky and Tennessee, or the back country of Pennsyl vania, Virginia and the Carolinas. While Missouri had few planta tions, the slave population kept proportional pace with the whites. Slavery was less economic than patriarchal.
The first steamboat reached St. Louis in 1816 and the Boonslick in 1819. The river transports carried out wheat, corn and meat products, as well as tobacco and hemp from the Missouri river counties, and the Missouri mule was early in evidence. St. Louis was the centre of the fur trade on the upper Mississippi and par ticularly on the Missouri; in the '20S the traders reached the Rocky Mountains and beyond. In the same decade began the overland trade with the Mexican hinterland at Santa Fe. When the Oregon trail was opened Missourians were the largest ele ment of the early settlement in that territory; in the '4os began the exodus to California over the California trail. The starting point of these three transcontinental routes was at the great bend of the Missouri at Westport Landing (now Kansas City).