Johnstown, WY has a population of 202 and is the 24,388th largest city in the United States. The population density is 6 per sq mi which is 9% higher than the Wyoming average and 93% lower than the national average. The median age in Johnstown is 50 which is approximately 37% higher than the Wyoming average of 37. In Johnstown, 53% of the population over 15 years of age are married, 77% speak English and 0% speak Spanish. 58% of Johnstown residents were born in Wyoming, 40% were born out of state, 1% were born outside of the United States and 0% were foreign born.