Oneida is a city in Nemaha County, Kansas, United States. As of the 2020 census, the population of the city was 61. Oneida was laid out circa 1…Oneida is a city in Nemaha County, Kansas, United States. As of the 2020 census, the population of the city was 61. Oneida was laid out circa 1873 and was named after the Oneida people. The town's streets were named after the main thoroughfares of Chicago.