Nampa, Eagle and Kuna aren’t shrinking. So why do these population estimates show that?
New estimates say the populations of some Treasure Valley cities have decreased. But that doesn’t mean they actually have fewer people living there, according to the local planning agency that just published the estimates.
How can this be?
The Community Planning Association of Southwest Idaho, or Compass, released 2022 population estimates Thursday with estimates for each city in Ada and Canyon counties. The population estimates are smaller than 2021’s in seven cities: Nampa, Eagle, Kuna, Parma, Wilder, Greenleaf and Melba.
But Compass Principal Planner and Demographer Carl Miller said that has to do with how Compass made its estimate. He said these cities’ populations likely didn’t decrease.
The annual estimates take the most recent data from the Census Bureau, conducted once every 10 years, and add in factors like new residential building permits, vacancy rates from Idaho Power, and typical household size based on location.
“From 2010 to 2021, we were using the 2010 census as the baseline, and then we built off that,” Miller said in a video interview. “In 2022, that was kind of a reset with the 2020 numbers. So we got new counts but we also got new household sizes, so we had to reset those numbers.”
Boise’s estimated population increased 0.8%, from 241,590 to 243,570. Meridian’s estimated population increased 4.4%, from 127,890 to 133,470.
Nampa, the third biggest city in Idaho, had a 1.7% decrease from 110,980 to 109,120. Miller attributed any decrease from last year to this year to the adjustments made because of the new census data.
“It’s not like everybody’s moving out of Nampa,” Miller said. “Nampa is more popular than ever.”
The new estimated population of Ada (532,710) and Canyon (249,720) counties combined is 782,430 — up 2.7% from last year’s 761,680.
(New data from the Census Bureau released last month estimated Ada County’s population in 2021 at 511,931, the first time the county surpassed half a million people. The Census Bureau estimated Canyon County’s 2021 population at 243,115. The combined total of just over 755,000 is about 6,600 fewer people than Compass estimated.)
Compass has tracked building permits and new residential units in the Treasure Valley for the past 20 years. The past three years have accounted for three of the top four of those years, according to a Compass report.
Ada and Canyon counties added 10,295 new units in 2019, then 9,171 units in 2020 and 10,883 in 2021. Only in 2005 were more units added (11,039).
When the COVID-19 pandemic began in 2020, Miller said he wasn’t sure how it would affect the area’s population growth. The growth hasn’t slowed down at all.
Compass projects the two counties to have a population of 907,910 in 2030 and 1,075,000 in 2050.
“While we’re seeing unprecedented growth currently, we know that there’s going to be seasons and fluctuations,” Miller said. “I don’t think it’ll stay at quite these rates for the next 20-plus years, but we are expecting the Treasure Valley to be a real robust area for growth now and into the future.”
Idaho and its cities have consistently ranked among the fastest-growing in the country. According to the 2020 census, Idaho was the second fastest-growing state in the previous decade, behind only Utah. In 2021, Idaho ranked first in percentage of population growth for the fifth consecutive year. Meridian was the fourth fastest-growing city nationally from 2010 to 2020.
Here are the newest population estimates:
- Ada County: 532,710
- Boise: 243,570
- Meridian: 133,470
- Eagle: 33,960
- Kuna: 27,480
- Star (Ada): 14,950
- Garden City: 13,040
- Unincorporated Ada County: 66,240
- Canyon County: 249,720
- Nampa: 109,120
- Caldwell: 66,450
- Middleton: 10,720
- Parma: 2,120
- Wilder: 1,620
- Greenleaf: 840
- Notus: 620
- Melba: 580
- Star (Canyon): 280
- Unincorporated Canyon County: 57,370
