Hollenberg, KS has a population of 20 and is the 28,787th largest city in the United States. The population density is 272 per sq mi which is 676% higher than the Kansas average and 200% higher than the national average. The median age in Hollenberg is 65 which is approximately 78% higher than the Kansas average of 36. In Hollenberg, 90% of the population over 15 years of age are married, 100% speak English and 0% speak Spanish. 20% of Hollenberg residents were born in Kansas, 80% were born out of state, 0% were born outside of the United States and 0% were foreign born.