Johnston is home to 24,384 people in Iowa. The population has roughly tripled since 2000, adding 15,735 people. This is an unusually credentialed place: 58% of adults have a four-year degree. Few US cities rank higher on income. Households here earn about 42% more than in Iowa as a whole. Getting to work takes 20 minutes on average.
At a glance
Wealthier
median household income $106,551, above the US median
US median: $82,259
Younger
median age 37.4
US median: 38.9
More educated
58% hold a bachelor's degree
US average: 36%
Stable housing
home values roughly flat, inflation adjusted
US median home: $376,019
Unique to this place
What stands out about Johnston
What changed most since 1990
Population4,702 → 24,384(+419%)US over the same years: +35%
Black share0.0% → 10.6%(+10.6 pts)US over the same years: +0.2 pts
Adults with a bachelor's degree33.8% → 57.8%(+24.0 pts)US over the same years: +15.3 pts
Johnston's population equals 4.8% of Polk County's. Its number of households without a car equals 1.9% of the county's. Its number of adults with a bachelor's degree or higher equals 6.6% of the county's.
Shares are "alone or in combination": a person with both Medicare and Medicaid counts in each, so categories overlap and do not sum to 100%.
Section 09 · Service history
Veterans
Veterans by period of service, 2024
Gulf War (2001 or later)19.8%(164)
US avg: 26.4%
Gulf War (1990s)20.6%(171)
US avg: 24.3%
Vietnam era22.5%(187)
US avg: 33.1%
Korean War8.2%(68)
US avg: 4.5%
World War II3%(25)
US avg: 1%
Share of the 830 veterans here. A veteran who served across eras counts in each, so shares can total more than 100%. Peacetime-only service is included in the total but not shown as an era.
BAR + DOT: THIS PLACE · TICK: US AVERAGE
Over time
Johnston, decade by decade
Johnston population, inflation-adjusted income and home value, education, and diversity by year
Year
Population
Median household income
Median home value
Bachelor's degree+
Diversity score
1990
4,702
$103,289
$230,407
33.8%
5.5
2000
8,649
$138,617
$341,378
49.9%
11.3
2010
17,278
$128,684
$340,510
48.6%
24.2
2020
24,064
$112,700
$330,281
53.3%
42.6
2024
24,384
$106,551
$369,100
57.8%
50.7
Census years come from the decennial census and the latest year from the American Community Survey, so part of any change between those two rows can reflect the different surveys. Dollar figures are adjusted for inflation to 2024 dollars; a figure ending in "+" was at the Census Bureau's reporting cap that year. The diversity score runs from 0 to 100; see how it's calculated.
