Cyrus McCormick

The eldest son of Robert and Maryann, Cyrus McCormick is credited as the inventor of the mechanical reaper. His father worked on creating a reaper machine for twenty years before giving up. Cyrus reconfigured his father's work and produced a working reaper in 1831. He patented the machine in 1834 and sold units on his family's plantation in Raphine, VA. However, sales were low.

In 1847, he moved to Chicago and sales skyrocketed. This was due in part to farmers purchasing the machine on credit and his dedication to advertising and demonstrations. He promised his customers his machine could process "15 acres a day." By 1860, he was selling over 4,000 reapers per year.

In 1871, the Great Chicago Fire destroyed his factory. He quickly rebuilt and continued to profit. 

After his death, the McCormick Harvesting Machine Company merged with the International Harvester Company.

William McCormick

A producer of agricultural equipment like his father and brothers, William McCormick made most of his fortune in Chicago. He started by assisting his brother Cyrus in his business in 1850. He mainly handled day-to-day operations while Cyrus was away. Later in life, he invested in real estate and moved to Europe. 

Leander McCormick

Leander James McCormick was born to Robert Hall and Maryann (Polly) Grigsby McCormick on February 8, 1819 in Rockbridge County, Virginia.  He was raised at the family homestead Walnut Grove, located near Steele's Tavern.  Robert Hall McCormick invented the mechanical reaper, for which his son Cyrus later received the patent. Leander eventually developed multiple improvements to the reaper and received patents for two of them, with the remainder being patented by his brother Cyrus.  At age 26, Leander married Henrietta Hamilton on her parents' homestead, Locust Hill, in Rockbridge County on October 22, 1845. The following year Robert McCormick died and his three living sons--Leander, Cyrus and William--established themselves in a business run by Cyrus to manufacture the reaper and sell it across the mid-west. This led the McCormick family, including Leander's wife and infant son, Robert Hall, to move to Chicago in November 1848. There they created what eventually became the McCormick Harvesting Machine Company with Leander taking over management of the manufacturing department, which he controlled for the next 30 years. By 1870, the McCormicks were one of the wealthiest families in the U.S.

In 1871, the great fire in Chicago destroyed much of the Reaper Works and other buildings, as well as the Leander McCormick family residence at the corner of Rush and Ohio streets, including pictures and ancestral souvenirs. Leander, his wife and children fled their burning home in early morning hours, moving to the west side of the city for the next several years. The McCormicks, under Leander's direction, quickly rebuilt and recovered. By 1879, the business had fully recovered and was merged into a corporation. Leander stayed active in the management of the business until 1889 when he retired and sold his shares to his nephew, Cyrus H. McCormick.
 

In his later years, Leander McCormick remained in Chicago and began to research the McCormick genealogy. He eventually produced and published works on the McCormick family.