In 1847, Cyrus Hall McCormick founded the McCormick Harvesting Machine Company focusing on manufacturing harvesting equipment. In 1902, they merged with the Deering Harvester Company, along with three smaller agricultural equipment firms, and became known as the International Harvester Company.
In 1905, they began experimenting with
very large machines, the earliest tractors, that were useful for farming huge tracts of land but too cumbersome for small farms.
Their first small tractor, the Mogul 8-16, was successful and caused the company to refine and improve their line. In 1939, they introduced their letter series tractors.
International Harvester became one of the largest tractor manufacturers and held that position in the industry for many years. However, with the decline of small farms, their hold slipped and in 1985, the company was taken over by Tenneco and then merged into the Case Corporation. More IH history details can be found by clicking here.
My Grandfather bought a new 1940 International Harvester M and used it the rest of his life. Unfortunately, between his death in 1982 and us purchasing the farm in 1988, it fell into disrepair and Grandma sold it. We do have two IH's on the farm and they are not "trailer tractors." They are both used as work tools.