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.
Rio Grande River
Russia claimed it.
The US claimed what became the New Mexico territory during the Mexican-American War. It was primarily a linear western extension from Texas.
Russia claimed it.
No. Cozumel is in Mexico, which is not part of Texas or the US for that matter.
There were a few Mexican settlements in the United States before they were claimed or fought for by the US government. These include Texas, New Mexico, Arizona, part of California, and a few others.
Mexican Cession (i.e. Texas)
Spain claimed Texas. It was in 1492. ha ha ha
west
Yes.
A cautious foreign policy with Mexico which still claimed Texas and the admitting of Texas, which had slavery, would increase the power of the slaveholding block in the US Congress.