The Public Math

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How fast is Williamson County growing? (DRAFT – not published)

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In short

  • About 752,800 people lived in the county on July 1, 2025.1
  • That is up about 24% since the 2020 census, from about 609,100 (our math).12
  • In the last year the county added about 23,800 people, roughly 65 a day (our math). About 6 in 10 moved here from elsewhere in the U.S.12

Numbers marked “our math” are our estimates, not official figures. The notes show the inputs and the steps.

How it works

  • The U.S. Census Bureau counts everyone every 10 years. In between, it makes yearly estimates as of July 1.1
  • Each estimate is built from three parts: births minus deaths, people moving in from other states or counties, and people moving in from other countries.1
  • Each new release can revise past years. So a 2024 number in this year’s file may not match last year’s file.1

What the numbers show

County2020 census baseJuly 2025Change since 2020 (our math)Added last year
Williamson609,059752,827+23.6%23,814 (+3.3%)
Travis1,290,1571,389,670+7.7%14,749 (+1.1%)
Hays241,064304,390+26.3%10,051 (+3.4%)
Collin1,066,2011,297,179+21.7%42,966 (+3.4%)
Fort Bend823,997975,191+18.3%24,163 (+2.5%)
Texas29,149,49831,709,821+8.8%391,243 (+1.2%)

Source: U.S. Census Bureau, 2025 county estimates.1

  • Where Williamson’s 2024-25 growth came from: 14,764 people moved in from other U.S. places, 4,618 from other countries, and births beat deaths by 4,552.1
  • Travis County lost people to other U.S. places (6,590 more moved out than in), while Williamson gained.1

The other side

  • Estimates are not counts. They can be off, and the Census Bureau revises them. The true number will not be known until the 2030 census.1
  • Different reports use different numbers. The county’s own audit used 727,480 for both 2024 and 2025. The Census figure is newer and covers July 1, 2025.1
  • Fast growth is not only a cost. New residents also add taxable homes and businesses. Whether growth pays for itself depends on many things this page does not measure.

Questions to ask

  • Which population number does each county budget forecast use?
  • How do county service plans for the jail, EMS and roads account for growth?

Changes to this page

  • Nov. 2, 2026: Rewrote the questions to ask so each is open, neutral and addressed to the public body.

What we still don’t know

  • How growth splits between cities and unincorporated areas in 2025.
  • How the 2026 estimate will change these numbers.

Footnotes

  1. U.S. Census Bureau, Vintage 2025 county population estimates (CO-EST2025-ALLDATA): April 1, 2020 estimates base; July 1, 2024 and 2025 estimates; 2024-25 change and its parts (natural change, domestic migration, international migration). Williamson 609,059; 729,013; 752,827; change 23,814; natural 4,552; domestic 14,764; international 4,618. Travis domestic −6,590. https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/counties/totals/co-est2025-alldata.csv ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8 ↩9 ↩10 ↩11

  2. Our math. 752,827 ÷ 609,059 = +23.6%; 23,814 ÷ 365 = 65 a day; 14,764 ÷ 23,814 = 62%; 23,814 ÷ 729,013 = +3.3%. Other rows: July 2025 ÷ 2020 base, and last-year change ÷ July 2024. ↩ ↩2

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