Omaha is a village in Gallatin County, Illinois, United States. The population was 209 at the 2020 census. Omaha was established in 1871 as a stop along the Springfield and Illinois South Eastern Railway. A baggage master working for the railroad, Henry Pearce, named the settlement for Omaha, Nebraska, where he had previously worked a…Omaha is a village in Gallatin County, Illinois, United States. The population was 209 at the 2020 census. Omaha was established in 1871 as a stop along the Springfield and Illinois South Eastern Railway. A baggage master working for the railroad, Henry Pearce, named the settlement for Omaha, Nebraska, where he had previously worked as a baggage master. After an initial attempt at incorporation failed in 1875, Omaha successfully incorporated in 1888.