By 1850 the national territory stretched over forest, plain and mountain. Within these far-flung limits dwelt 23 million people in a union comprising 31 states. In the East, industry boomed. In the Midwest and the South, agriculture flourished. After 1849 the gold mines of California poured a golden stream into the channels of trade.  

New England and the Middle Atlantic states were the main centers of manufacturing, commerce and finance. Principal products of these areas were textiles, lumber, clothing, machinery, leather and woolen goods. At the same time, shipping had reached the height of its prosperity, and vessels flying the American flag plied the oceans, distributing wares of all nations.  

The South, from the Atlantic to the Mississippi River and beyond, was a relatively compact political unit featuring an economy centered on agriculture. Tobacco was important to the economies of Virginia, Maryland and North Carolina. In South Carolina, rice was an abundant crop, and the climate and soil of Louisiana encouraged the cultivation of sugar. But cotton eventually became the dominant crop and the one with which the South was identified. By 1850 the American South grew more than 80 percent of the world's cotton. Slaves were used to cultivate all these crops, though cotton most of all.  

The Midwest, with its boundless prairies and swiftly growing population, flourished. Europe and the older settled parts of America demanded its wheat and meat products. The introduction of labor-saving implements--notably the McCormick reaper -- made possible an unparalleled increase in farm production. The nation's wheat crops meanwhile swelled from some 35 million hectoliters in 1850 to nearly 61 million in 1860, more than half being grown in the Midwest.  

An important stimulus to western prosperity was the great improvement in transportation facilities; from 1850 to 1857 the Appalachian Mountain barrier was pierced by five railway trunk lines linking the Midwest and the East. These links established the economic interests that undergirded the political alliance of the Union from 1861 to 1865. In the expansion of the railway network, the South at first had much less part. It was not until the late 1850s that a continuous line ran through the mountains connecting the lower Mississippi River with the southern Atlantic seaboard.