Originally named Calhoun, after Senator John C. Calhoun of South Carolina, Springfield was settled by trappers and traders who came to the Sangamon River in 1818 due to the fertile soil and trading opportunities. The first settlers migrated to the area from Kentucky, Virginia, and North Carolina. The settlement became the seat of Sangamon County in 1821. By 1832, Senator Calhoun had fallen out of the favor with the public and the town was renamed Springfield. With the support of Abraham Lincoln, who called Springfield his home at that time, the city became the third and current capital of Illinois in 1839. The designation was largely due to the efforts of Abraham Lincoln and his associates; nicknamed the "Long Nine" for their combined height of 54 feet.

Railroads arrived in 1852, which led to an increase in economic activity. When Lincoln left to take the office of president in 1861, the population had risen to nearly 10,000. Soon after the Civil War, the first coal mine shaft was sunk in Springfield, which opened an industry that became important to the area and Springfield became a major hub in the Illinois railroad system. By the turn of the century, Springfield, Illinois was no longer the small town in which Abraham Lincoln lived, but a growing industrial center. The population of Springfield had grown at an alarming rate; it had nearly doubled since the last shot of the Civil War was heard in 1865. The numbers of people moving into Springfield increased faster than the creation of new jobs. The new workers added more tension to an already tight job market. The southern blacks emigrants and new European immigrants vied with white workers for factory and coal mining jobs.

Sources:
http://www.u-s-history.com/pages/h2082.html
http://en.wikipedia.org/wiki/Springfield,_Illinois
http://library.thinkquest.org/2986/