In 1863, he built a farm on the present location of Windsor, Colorado. (Mike Peters, Greeley Tribune, "How Weld Towns Got Their Name"). He returned to Louisa County, Iowa in 1864 and married Rebecca J. Hill, his second wife. Together they crossed the Great Plains with his second wife that year and settled in Weld County along its western border with Larimer County, establishing a livestock raising operation. He was an early prominent citizen of Fort Collins, the nearest post office and trading point, and was a charter member of the Masonic Lodge there. In 1866, he was elected as Justice of the Peace, serving in that capacity for nine years. For six years, he served concurrently as a county commissioner. Eaton and Rebecca Hill had three children: Lincoln Eaton, Bruce Grant Eaton, and Jennie Bell Eaton. In 1870 Eaton met Nathan Meeker, whom newspaperman Horace Greeley had dispatched to Colorado to pick the Union Colony site. Eaton suggested the land southeast of his place, at the confluence of the South Platte and Poudre Rivers. Eaton promised to assist the ditch construction that would be critical to the colony's farms. Bankrolled by Horace Greeley, the Union Colonists secured 60,000 contiguous acres. On March 15, 1870, the executive committee named the town "Greeley." Gophers continually thwarted the 35-mile Canal No. 1 but, according to Union Colony minutes, Eaton would not give up. Eaton expanded his operations from farming into contracting, specializing in the building of irrigation canals and reservoirs, a business he heavily promoted as a means of bringing growth and wealth to Larimer and Weld Counties. In 1873, in association with John C. Abbott, he built what later became known as Larimer County Canal No. 2, which watered large areas of land west, south, and southwest of Fort Collins. Competition for water between Fort Collins Agricultural Colony and the Greeley became desperate and in 1874 almost led to gunfire. Ben Eaton and a few others calmed Greeley colonists with a commitment to divide the water according to need and a promise to deliver it. The promise was not necessary because it rained. In 1878 he began construction of the Larimer and Weld Canal, once known as the Eaton Ditch. The Larimer and Weld Irrigation Company was incorporated on March 10, 1879. The company's board of directors were James Duff, Hyde Sparkes, Benjamin H. Eaton, Thomas B. Dunbar, and Aaron J. Eaton.