Papillion is a city in and the county seat of Sarpy County, Nebraska, United States. The city developed in the 1870s as a railroad town and is a southwest suburb of Omaha. The city is part of the larger five-county metro area of Omaha. Papillion's population was 24,159 at the 2020 census, making it the 7th most populous city in Nebraska. Its growth since the late 20th century has reflected Omaha's.