Longmont began in an unusual way. In 1870, a group of prominent men in Chicago decided to start a new town in Colorado. They sold memberships in this new town they called the "Chicago-Colorado Colony." The money raised paid for 60,000 carefully chosen northern Colorado acres of land for a town site and nearby farms. They planned the town, and brought the people, lumber and building materials to the barren site. By the summer of 1871 they had built a small town and named it "Longmont," in honor of "Longs Peak," the mountain formation they could clearly see from town.
While the climate of Longmont is dry, the soil is rich, and will produce excellent crops if water is brought to it. One of the great achievements of the Chicago-Colorado Colony was building large irrigation ditches to bring water from the rivers to the fields of wheat, fruit trees and peas that farmers planted.
The Colony planners designed Longmont to look like many other towns in America. The original one-square-mile plan had stores along Main Street, homes arranged in a grid spreading out from Main Street and industrial buildings located along the railroad and the St. Vrain River.
As the town grew, large-scale agricultural industries arrived, first flour mills in 1872, then the Empson vegetable cannery in 1889. Several leading residents of Longmont worked together to build a sugar beet factory on the east edge of town. They had developed enough support by 1903 to build what would soon become the Great Western Sugar Co. Sugar beets grew well in northeastern Colorado because of the availability of irrigation water and the richness of the soil.
The richness of Longmont 's soil attracted many people. People came from Sweden and settled northwest of Longmont. Germans came by way of Russia, and farmed the sugar beet fields. People came from Mexico to work in the fields. People came from Japan, and set up vegetable farms. All these groups continue to be an important part of Longmont's heritage, and their descendants still live in and around Longmont.