Hollenberg is a city in Washington County, Kansas, United States. As of the 2020 census, the population of the city was 10. It is located 1.5 m…Hollenberg is a city in Washington County, Kansas, United States. As of the 2020 census, the population of the city was 10. It is located 1.5 miles south of the Nebraska state line. Hollenberg was laid out in 1872. It was named for its founder, G. H. Hollenberg, who owned a store at the site.