The people of Alta California were given the option or relocating south beyond the new Mexican border or accepting U.S. citizenship. About 90% took the citizenship option.
I had also heard that by the time Texas decided to secede from Mexico (and from the state of Coahuila y Tejas), the ratio of illegal immigrants from the United States to Mexicans was about 6 to 1!
they all left
The Mexican Cession was acquired in 1848 at the Treaty of Guadalupe Hidalgo.
The Southwest, including California, was taken "by force of arms" from Mexico, during the Mexican War.
From the Mexican Cession of the Treaty of Guadalupe Hidalgo.
the Mexican cession was the result of war with Mexico.
The Mexican cession was signed at Guadalupe-Hidalgo in 1948.
The mexican cession cause people to get more land
1848 Mexico recognized Texas was part of the US and that the Rio Grande was the border of the two nations. They ceded the Mexican Cession. The US, in return, paid Mexico about $18 million for claims and to protect the Mexicans who lived in Texas and the Mexican Cession.
They got the Mexican cession cuz when they became independent from Spain.
The Mexican-American War, and the resulting Mexican Cession, were during the presidency of James K. Polk.
The Texas annexation purchased the Mexican cession.
the United states paid Mexico $15 million dollars for this land, which became known as the mexican cession