Separate Regions

By 1850, Americans are heading west in great numbers. There are actually two separate migration routes, one in the North and another in the South. The southern route is used to spread plantation slavery.

In the South, the entire economy is based on the plantation. The crop changes over time, but the plantation method remains constant, and with it, the total dependence upon a large slave labor force. 

In the North, by contrast, the economy has been continually shifting. Shipping, fishing and lumbering were important in the early years, but manufacturing and railroads are the big new things.
Population migration routes, 1850 map

  Two Migration Routes
America has been divided since the very beginning, as Northerners and Southerners have never really mixed. Everything about North and South is separate. Separate economies, separate business interests, and separate views on slavery. Congress has kept a lid on this problem by making sure that regional power in Congress remains roughly balanced. This is about to change.

Spread of slavery, 1850 map

  Cotton-Belt Slavery
Previously, the institution of slavery had been slowly withering away in the South, as the profitability of tobacco plantations declined. Some Southerners even began to accept the possibility that slavery might eventually disappear altogether, as planters continued to abandon tobacco country. The arrival of the cotton gin changes all that, and slaves are again in high demand. The areas highlighted in ORANGE above indicate the extent of slavery by 1850. The brighter the ORANGE, the greater the density of slaves. 


Mexican War, 1846-1848 map

  Southwestern Expansion
The war with Mexico is triggered by events in Texas, where independent ranchers briefly establish the Republic of Texas, in 1836. Mexico continues to claim ownership, but American settlers eventually coax Congress into annexing the territory, in 1845. Within a year, border clashes turn into a full-blown war, which lasts two years, and is fought entirely in Mexican territory. When it's over, America owns not only Texas, but also a huge new tract of land including all-important California.