Burr Ridge's gently rolling hills were carved by glaciers at the end of the last ice age, and most of the village lies on the Valparaiso Moraine. Flagg Creek, a tributary of the Des Plaines River, runs through town. In 1917 the International Harvester Company purchased 414 acres (1.7 km2) for an experimental farm, where it tested the world's first all-purpose tractor, the Farmall. Also in 1917, the Cook County Prison Farm (also known as the Bridewell Farm) began operation in what is now Burr Ridge.