Land acquired through the mexican cession is located today in
the northeastern us.
the northwestern us.
the southeastern us.
the southwestern us.

 the southwestern US.

Context/detail:

The Mexican Cession was territory ceded (meaning given up) to the United States in 1848 after the Mexican-American War.  The territory included lands that represent the full states of California, Nevada, and Utah, as well as large portions of  Arizona and New Mexico, and about a quarter of what would become the state of Colorado.  There was also a small section of Wyoming involved.  So that represents the bulk of territory that is in Southwest of the present United States.

basic principles: federalism, separation of powers, checks and balances, judicial review, representative democracy, limited government, rule of law, individual rights and responsibilities, consent of the governed, majority rule, popular sovereignty, equal protection.