1836 – Texans celebrate the first Texas Independence Day with the signing of the Texas Declaration of Independence, officially broke Texas from Mexico, and creating the Republic of Texas
. The Republic of Texas was an independent sovereign country in North America that existed from March 2, 1836, to February 19, 1846. It was bordered by the nation of Mexico to the southwest, the Gulf of Mexico to the southeast, the two U.S. states of Louisiana and Arkansas to the east and northeast, and the United States territories encompassing the current U.S. states of Oklahoma, Kansas, Colorado, Wyoming, and New Mexico to the north and west. The citizens of the republic were known as Texians. Formed as a separate nation after gaining independence from Mexico in 1836, the republic claimed borders that included all of the present U.S. state of Texas as well as parts of present-day Oklahoma, Kansas, Colorado, Wyoming, and New Mexico based upon the Treaties of Velasco between the newly created Texas Republic and Mexico. The eastern boundary with the United States was defined by the Adams-Onís Treaty between the United States and Spain in 1819. Its southern and western-most boundary with Mexico was under dispute throughout the entire existence of the republic with Texas claiming the boundary as the Rio Grande (known as the Río Bravo del Norte or Río Bravo in Mexico), and Mexico claiming the boundary as the Nueces River. This dispute would later become a trigger for the Mexican–American War from 1846 to 1848 between Mexico and the United States after the annexation of Texas by the United States on December 29, 1845.