Sun Prairie, Wisconsin Population

Current Population

39,227

Estimated July 1, 2025

+3,214 residents(+8.9%)since 2020

Annual change+0.3%2024–2025

Latest Official Census

35,967

2020 Census

cityDane County

Population Over Time

Estimated population changed from 36,013 in 2020 to 39,227 in 2025.

Annual population estimates by year.
Year	Population	Change	% change
2020	36,013	—	—
2021	36,661	+648	+1.8%
2022	37,492	+831	+2.3%
2023	38,332	+840	+2.2%
2024	39,101	+769	+2%
2025	39,227	+126	+0.3%

2020 Census (official count): 35,967

Census History

Official Decennial Census counts. Each is an enumeration taken on April 1 of its census year, separate from the annual estimates above.

Official Decennial Census counts by census year.
Census	Population
2010 Census	29,364
2020 Census	35,967

Insights

Sun Prairie's population grew 22.5% from 2010 to 2020.
Source: U.S. Census Bureau — 2020 Census Redistricting Data (P.L. 94-171), table P1
How this was determined
Strongest eligible observation in category "change" (score 70.5, confidence 75); chosen from 1 eligible candidate(s).
Compared against: U.S. places
Confidence: 75/100
Sun Prairie is Wisconsin's 20th-largest incorporated place by population.
Source: U.S. Census Bureau — Subcounty Resident Population Estimates (SUB-EST2025), Vintage 2025
How this was determined
Strongest eligible observation in category "perspective" (score 71.25, confidence 85); chosen from 1 eligible candidate(s).
Compared against: incorporated places in Wisconsin
Confidence: 85/100

Sources & Methodology

The current population figure is an annual estimate from the U.S. Census Bureau's Population Estimates Program. The 2020 Census is shown separately as the official benchmark.

Current estimate — 39,227 · July 1, 2025

U.S. Census Bureau — Subcounty Resident Population Estimates (SUB-EST2025), Vintage 2025

Official Census — 35,967 · April 1, 2020

U.S. Census Bureau — 2020 Census Redistricting Data (P.L. 94-171), table P1

These figures can differ because the Census and annual population estimates are produced at different times using different methods. Both are shown so you can distinguish the most current estimate from the official Census benchmark.

How the change since 2020 is calculated

Both endpoints come from the same Census Bureau Population Estimates Program release, so the comparison is like for like: 36,013 on July 1, 2020 and 39,227 on July 1, 2025. The change is the later estimate minus the earlier one (+3,214), and the percentage is that change divided by the 2020 estimate (+8.9%). The Decennial Census count is never used as an endpoint here — it is an enumeration on a different reference date, produced by a different method, so subtracting one from the other would measure the difference between two methods as well as the change in population.