From a total population of 15,691, Johnston has a median age of 38.1. The average age of males, in Johnston, is 37.9 while the average age of females is 38.4. When you compare this to median age of Iowa, Johnston is 0.1 years older.
The median income of individuals, in Johnston, is $45,520 while the average household income is $94,821. When comparing the median income of people living in Johnston to the rest of Iowa, the average income in Johnston is $17,899 more.