Sam Houston in the context of "Huntsville, Texas"

Houston is the most populous city in the U.S. state of Texas and the Southern United States. It is the fourth-most populous city in the United States, with a population of 2.3 million at the 2020 census. The Greater Houston metropolitan area, at 7.8 million residents, is the fifth-most populous metropolitan area in the nation and second-most populous in Texas. Located in Southeast Texas near Galveston Bay and the Gulf of Mexico, Houston is the seat of Harris County. Covering a total area of 640.4 square miles (1,659 km), it is the ninth largest city in the country and the largest whose municipal government is not consolidated with a county, parish, or borough. Although primarily located within Harris County, portions of the city extend into Fort Bend and Montgomery counties. Houston also functions as the southeastern anchor of the Texas Triangle megaregion.

Houston was founded by land investors on August 30, 1836, at the confluence of Buffalo Bayou and White Oak Bayou (a point now known as Allen's Landing) and incorporated as a city on June 5, 1837. The city is named after former General Sam Houston, who was president of the Republic of Texas and had won Texas's independence from Mexico at the Battle of San Jacinto 25 miles (40 km) east of Allen's Landing. After briefly serving as the capital of the Texas Republic in the late 1830s, Houston grew steadily into a regional trading center for the remainder of the 19th century. The 20th century brought a convergence of economic factors that fueled rapid growth in Houston, including a burgeoning port and railroad industry, the decline of Galveston as Texas's primary port following a devastating 1900 hurricane, the subsequent construction of the Houston Ship Channel, and the Texas oil boom. In the mid-20th century, Houston's economy diversified, as it became home to the Texas Medical Center—the world's largest concentration of healthcare and research institutions—and NASA's Johnson Space Center, home to the Mission Control Center.

The Republic of Texas was the only state to enter by treaty into the United States and admitted to the Union as the 28th state on December 29, 1845.

The Republic of Texas declared independence from the Republic of Mexico on March 2, 1836. It applied for annexation to the United States the same year, but was rejected by the United States secretary of state, John Forsyth, under President Andrew Jackson. At that time, the majority of the Texian population favored the annexation of the Republic by the United States. The leadership of both major U.S. political parties (the Democrats and the Whigs) opposed the introduction of Texas – a vast slave-holding region – into the volatile political climate of the pro- and anti-slavery sectional controversies in Congress. Moreover, they wished to avoid a war with Mexico, whose government had outlawed slavery and refused to acknowledge the sovereignty of its rebellious northern province. With Texas's economic fortunes declining by the early 1840s, the president of the Texas Republic, Sam Houston, arranged talks with Mexico to explore the possibility of securing official recognition of independence, with the United Kingdom mediating.

The Treaties of Velasco were two documents, one private and the other public, signed in Fort Velasco on May 14, 1836 between General Antonio López de Santa Anna and the Republic of Texas in the aftermath of the Battle of San Jacinto on April 21, 1836. The part of the former Velasco, Texas, in which the fort was located is now part of the present-day location of Surfside Beach. The signatories were Interim President David G. Burnet for Texas and Santa Anna for Mexico. Texas intended the agreements to conclude hostilities between the two armies and offer the first steps toward the official recognition of Texas's independence from Mexico.

Santa Anna had been captured by Texans. Many wanted him hanged as just vengeance for the murder of comrades and family during the battles at Alamo and Goliad, but Sam Houston spared his life and extracted a promise from Santa Anna that Mexican troops would be removed from Texas. Santa Anna persuaded Burnet that if he were allowed to return to Mexico City, he would argue for the independence of Texas. Santa Anna signed both the public agreement and the secret treaty, but neither was ratified as a treaty by the Mexican government because he had signed them under duress while being held captive. Santa Anna later said, "I did promise to try to get a hearing for the Texas Commissioners, but this in itself did not bind the government to receive them."

The 1860 Constitutional Union National Convention met on May 9, 1860, in Baltimore, Maryland. It was the only national convention ever held by the Constitutional Union Party, which was organized largely by former Whig Party members from the Southern United States who opposed secession. The convention nominated former Senator John Bell of Tennessee for president and former Secretary of State Edward Everett of Massachusetts for vice president.

Bell won the presidential nomination on the second ballot of the convention, defeating Everett, Governor Sam Houston of Texas, Senator John J. Crittenden of Kentucky, former Governor William Alexander Graham of North Carolina, Associate Justice John McLean of Ohio, and several other candidates. In the 1860 presidential election, Bell and Everett finished third in the electoral vote and fourth in the popular vote.

Texas declared its secession from the Union on February 1, 1861, and joined the Confederate States on March 2, 1861, after it had replaced its governor, Sam Houston, who had refused to take an oath of allegiance to the Confederacy. As with those of other states, the Declaration of Secession was not recognized by the US government at Washington, DC. Some Texan military units fought in the Civil War east of the Mississippi River, but Texas was more useful for supplying soldiers and horses for the Confederate Army. Texas' supply role lasted until mid-1863, when Union gunboats started to control the Mississippi River, which prevented large transfers of men, horses, or cattle. Some cotton was sold in Mexico, but most of the crop became useless because of the Union's naval blockade of Galveston, Houston, and other ports.

The Battle of San Jacinto (Spanish: Batalla de San Jacinto), fought on April 21, 1836, in present-day La Porte and Deer Park, Texas, was the final and decisive battle of the Texas Revolution. Led by General Sam Houston, the Texan Army engaged and defeated General Antonio López de Santa Anna's Mexican army in a fight that lasted just 18 minutes. A detailed, first-hand account of the battle was written by General Houston from the headquarters of the Texan Army in San Jacinto on April 25, 1836. Numerous secondary analyses and interpretations have followed.

General Santa Anna, the president of Mexico, and General Martín Perfecto de Cos both escaped during the battle. Santa Anna was captured the next day on April 22 and Cos on April 24. After being held for about three weeks as a prisoner of war, Santa Anna signed the peace treaty that dictated that the Mexican army leave the region, paving the way for the Republic of Texas to become an independent country. These treaties did not necessarily recognize Texas as a sovereign nation but stipulated that Santa Anna was to lobby for such recognition in Mexico City. Sam Houston became a national celebrity, and the Texans' rallying cries from events of the war, "Remember the Alamo" and "Remember Goliad", became etched into Texan history and legend.

The Consultation, also known as the Texian Government, served as the provisional government of Mexican Texas from October 1835 to March 1836 during the Texas Revolution. Tensions rose in Texas during early 1835 as throughout Mexico federalists began to oppose the increasingly centralist policies of the government. In the summer, Texians elected delegates to a political convention to be held in Gonzales in mid-October. Weeks before the convention and war began, the Texian Militia took up arms against Mexican soldiers at the Battle of Gonzales. The convention was postponed until November 1 after many of the delegates joined the newly organized volunteer Texian Army to initiate a siege of the Mexican garrison at San Antonio de Bexar. On November 3, a quorum was reached in San Antonio. Within days, the delegates passed a resolution to define why Texians were fighting. They expressed allegiance to the deposed Constitution of 1824 and maintained their right to form the General Council. In the next weeks, the council authorized the creation of a new regular army to be commanded by Sam Houston. As Houston worked to establish an army independent from the existing volunteer army, the council repeatedly interfered in military matters.

After authorizing an expedition to take Matamoros, Mexico, the council named several men, simultaneously, to organize and lead the assault, angry at the effect the expedition was having on existing Texian garrisons, Smith dissolved the council. Alleging that Smith did not have the authority to disband them, council members impeached him and lieutenant governor James W. Robinson was named acting governor.