Built in 1831 by Virginia-born inventor Cyrus Hall McCormick (1809–84), the McCormick reaper was the first commercially successful machine to help farmers with their harvest. The device increased average production for American farmers in the mid-nineteenth century from 2 or 3 acres (0.8 or 1.2 hectares) a day to 10 acres (4 hectares) a day, greatly contributing to the agricultural boom in the antebellum South. The McCormick reaper, which had a blade attached to a drive wheel, was horse drawn and cut through grain stalks. The cut grain stalks then fell onto a platform and were collected with a rake by a worker. Because the reaper replaced as many as eight to 10 workers, many historians believe the invention played an important role in the outcome of the Civil War (1861–65) as farmers in the North had more widely adopted the machinery than farmers in the South. This allowed more northern farmhands to go into battle while wheat production continued, giving the North superior manpower, which was critical to the Union victory.
The McCormick reaper came into wide use by 1847. Around that time McCormick moved his growing business to Chicago, the heart of the expanding Midwestern farm market, so that he could transport his machines to the East and South via the Great Lakes and connected waterways. Within five years his business had become the largest farm implement factory in the world. Sales and distribution of McCormick's equipment increased further during the 1850s as Chicago became a center for the nation's then-expanding rail system.
Over time the company made improvements to the reaper. In the 1850s a self-raking feature was added, further reducing the amount of labor required to harvest grain. In the 1870s McCormick introduced a binder, which bound the sheaves of grain and dropped them to the ground to be collected. In the late 1800s the reaper (or harvester) was joined with another invention, the thresher, which separates grains from the stalks. The new reaper-thresher machine was called a combine. Today's combines still use the basic features of McCormick's revolutionary 1831 invention. In 1902 the McCormick company became International Harvester and in 1986 became Navistar Corporation.