Rio Grande River
Mexico claimed that the Nueces River was the boundary between the two nations while the US maintained that the Rio Grande was the boundary. As clear boundary definitions were never established, some skirmishes occurred on this no-man's land, resulting in American blood shed, and used as casus belli by President Polk to start the Mexican-American War (1846-1848).
the southern boundry was claimed because it has richer soil and a better climate to grow things.
The immediate reason for the Mexican-American War was that the two countries could not agree on which river formed the southern boundary of Texas. The Texans, and thus the US, claimed land as far south as the Rio Grande, but the southern boundary of the Mexican province of Texas (before it won its independence from Mexico) had been along the Nueces river, somewhat further north, and that was where the Mexicans said the border was. Mexico had also threatened war if the Republic of Texas was annex by the US, which it was in 1845. Many people in the US, including President Polk, also wanted to incorporate other northern Mexican territory, including California, in the US
It was not so much the fact of the US annexing Texas and adding it to the country. The issue which was contentious was the location of the southern boundary of Texas. The US and Texas before it contended that the boundary was the Rio Grande. Mexico contended that the ancient and traditional southern border of the former Mexican province of Tejas was the Nueces River. So the conflict was over ownership of the territory between the Nueces and the Rio Grande.
Right.
Houston, Texas is a city in the southern US.
Texas was originally part of Mexico. I believe Texas wanted to be its own country. The US claimed Texas after the war between the US and Mexico.
It is Texas.
The boundary was most the northern borders of the states Arkansas, Tennesee,Texas, and Virginia.
The US claimed what became the New Mexico territory during the Mexican-American War. It was primarily a linear western extension from Texas.
In 1802, the Mississippi River formed the western boundary of the United States. The southern boundary extended to the 31st parallel north latitude.
Texas