Otoe County is a county in the U.S. state of Nebraska. As of the 2010 United States Census, the population was 15,740. Its county seat is Nebraska City. The county was formed in 1854, and was named tor the Otoe Indian tribe.In the Nebraska license plate system, Otoe County is represented by the prefix 11 (it had the 11th-largest number of vehicles registered in the county when the license plate system was established in 1922).

Cass County is a county in the U.S. state of Nebraska. As of the 2010 United States Census, the population was 25,241. Its county seat and largest city is Plattsmouth. The county was formed in 1855, and was named for General Lewis Cass.Cass County is included in the Omaha-Council Bluffs, NE-IA Metropolitan Statistical Area.In the Nebraska license plate system, Cass County is represented by the prefix 20 (it had the 20th-largest number of vehicles registered in the county when the license plate system was established in 1922).

Mills County is a county located in the U.S. state of Iowa. As of the 2020 census, the population was 14,484. The county seat is Glenwood. The county was formed in 1851 and named for Major Frederick Mills of Burlington, Iowa who was killed at the Battle of Churubusco during the Mexican–American War.Mills County is included in the Omaha–Council Bluffs, NE–IA Metropolitan Statistical Area.

Sarpy County is a county located in the U.S. state of Nebraska. As of the 2020 United States Census, the population was 190,604, making it the third-most populous county in Nebraska. Its county seat is Papillion.Sarpy County is part of the Omaha-Council Bluffs, NE-IA Metropolitan Statistical Area.