Oconto is a village in Custer County, Nebraska, United States. The population was 151 at the 2010 census. The community was founded in 1887 as Olax, but the original name conflicted with another Nebraska location, so it was renamed to Oconto. The exact source of the name has been debated, some hold Oconto was the name of a pioneer settler, …Oconto is a village in Custer County, Nebraska, United States. The population was 151 at the 2010 census. The community was founded in 1887 as Olax, but the original name conflicted with another Nebraska location, so it was renamed to Oconto. The exact source of the name has been debated, some hold Oconto was the name of a pioneer settler, while others believe the town was named after Oconto, Wisconsin. Oconto was incorporated in 1906.