Answer:
In 1845, the United States of America attached Texas, which had won freedom from Centralist Republic of Mexico in the Texas Revolution of 1836. After Mexican powers assaulted American powers, the U.S. pronounced the Mexican– American War (1846– 1848).
The mid 1800s saw the United States rapidly develop in size. New settlers and new land implied a greater and more grounded nation. It likewise implied dislodging a huge number of Native Americans and the proceeded with spread of bondage.
The United States turned into a mainland country with the buy of Louisiana from France in 1803 and the settlement of the grounds past the Appalachian Mountains. Westbound development energized strife with Native populaces and prompted their constrained expulsion. By 1820, 2 million Americans lived west of the Appalachians, out of an all out national populace of 10 million.
The local societies that had created along the Atlantic Coast—New England, Middle Atlantic, Chesapeake, and Carolinas—were transplanted into the Old Northwest (Ohio, Indiana, Illinois, Michigan, and Wisconsin) and the Old Southwest (Arkansas, Kentucky, Louisiana, Missouri, Tennessee, and Texas). Be that as it may, in spite of the fact that Americans had started to distinguish themselves as a country, they were isolated by sectional interests that developed with quick industrialization and the subject of servitude.