Main article: Texas Annexation
Most Texans wanted their Republic to be annexed into the United States because of the Republic's defensive and financial difficulties. Events such as the Dawson Massacre and two recaptures of B?xar in Texas of 1842 added momentum to the desire for statehood. However, strong Northern opposition to adding another slave state blocked Texas's admission untilpro-annexation James K. Polk won the election of 1844. On 29 December 1845, Texas was admitted to the U.S. as a constituent state of the Union. Texas was the only state to enter the United States by treaty instead of territorial annexation. The Mexican-American War followed, with decisive victories by the U.S. Post war Texas grew rapidly as migrants poured into the cotton lands of the state.
Confederate States of America
Main article: Texas in the American Civil War
Just before the American Civil War, elected delegates met in convention and authorized secession from the U.S. on 1 February 1861. Texas voters later approved the measure in referendum, and the state was accepted as a charter member by the provisional government of the Confederate States of America on 1 March 1861. Partly due to its distance from the front lines of the war, a major role for Texas was to supply men, especially cavalry, for Confederate forces, many veterans of the Mexican-American War. Texan regiments fought in every major battle throughout the war. Texas was a "supply state" for the Confederate forces until mid-1863, when the Union capture of the Mississippi River made large movements of men or cattle impossible. The last battle of the Civil War was fought in Texas, at Palmito Ranch, on 12 May 1865, well after Lee's surrender on 9 April 1865 at Appomattox Court House in Virginia.
Texas descended into near-anarchy during the two months between the surrender of the Army of Northern Virginia and the assumption of authority by Union General Gordon Granger, as Confederate forces demobilized or disbanded and government property passed into private hands through distribution or plunder. Juneteenth commemorates the announcement of the Emancipation Proclamation on 19 June 1865 in Galveston by General Gordon Granger; nearly 1-1/2 years after the original announcement of 1 January 1863. President Johnson, on 20 August 1866, declared that civilian government had been restored to Texas. On 30 March 1870, despite not meeting all requirements for readmission, the Congress readmitted Texas into the Union.
The first major oil well in Texas was Spindletop, a little hill south of Beaumont, on the morning of 10 January 1901. Other oil fields were later discovered nearby in East Texas, West Texas, and under the Gulf of Mexico. The resulting "Oil Boom" permanently transformed the economy of Texas. Oil production eventually averaged three million barrels of oil per day at its peak in 1972. The economy, which had shown significant progress since the American Civil War, was dealt a double blow by the Great Depression and the Dust Bowl.
From 1950 through the 1960s, Texas modernized and dramatically expanded its system of higher education. Under the leadership of Governor John B. Connally, the state created a long-range plan for higher education, a more rational distribution of resources, and a central state apparatus designed to manage state institutions more efficiently. These changes, helped Texas universities receive federal research funds during the Kennedy and Johnson administrations.
Main article: Geography of Texas
The geography of Texas spans a wide range of features and timelines. Texas is the southernmost part of the Great Plains, which ends in the south against the folded Sierra Madre Oriental of Mexico. It is in the south-central part of the United States of America. It is considered to form part of the U.S. South and also part of the U.S. Southwest.
The Rio Grande, Red River and Sabine River all provide natural state lines where Texas borders Oklahoma on the north, Louisiana and Arkansas on the east, New Mexico on the west, and the Mexican states of Chihuahua, Coahuila, Nuevo Le?n, and Tamaulipas to the south.
Some residents divide Texas into five regions: North, East, Central, South, and West. Texas Almanac divides Texas into four physical regions: Gulf Coastal Plains, Interior Lowlands, Great Plains, and The Basin and Range Province. This is the difference between human geography and physical geography.
Some regions of Texas are more associated with the South than the Southwest (primarily East Texas, Central Texas, and North Texas), while others share more similarities with the latter (primarily far West Texas and South Texas). The upper Texas Panhandle and the South Plains parts of West Texas do not easily fit into either category. The former has much in common with the Midwestern United States, while the latter, originally settled primarily by anglo Southerners, yet with a notable Hispanic population, is somewhat of a blend of South and Southwest.
The size of Texas prohibits easy categorization of the entire state wholly in any recognized region of the United States; geographic, economic, and even cultural diversity between regions of the state preclude treating Texas as a region in its own right.
See also: Texas Irrigation Canals
Main article: Geology of Texas
Shaded Relief Map of the Llano Estacado
Texas is the southernmost part of the Great Plains, which ends in the south against the folded Sierra Madre Occidental of Mexico. The continental crust here is a stable Mesoproterozoic craton which changes across a broad continental margin and transitional crust into true oceanic crust of the Gulf of Mexico. The oldest rocks in Texas date from the Mesoproterozoic and are about 1,600 million years old. These Precambrian igneous and metamorphic rocks underly most of the state, and are exposed in three places: Llano uplift, Van Horn, and the Franklin Mountains, near El Paso. This is overlain by mostly sedimentary rocks. The oldest sediments were deposited on the flanks of a rifted continental margin, or passive margin that developed during Cambrian time. This margin existed until Laurasia and Godwana collided in Pennsylvanian time to form Pangea. This is the buried crest of the Appalachian Mountains-Ouachita Mountains-Marathon Mountains zone of Pennsylvanian continental collision. This