Premise: Ogallala is a city in Keith County, Nebraska, United States. The population was 4,737 at the 2010 census. It is the county seat of Keith County. In the days of the Nebraska Territory, the city was a stop on the Pony Express and later along the transcontinental railroad. The Ogallala Aquifer was named after the city.
Hypothesis: Ogallala is a city in Keith County, Nebraska.