Methodology & sources
Everything on these pages is derived from public federal data. This page documents exactly which files, what we did to them, and where the numbers' edges are.
Sources
| Used for | Source |
|---|---|
| National and state migration figures (gross in/out, net, state-to-state corridors) | IRS SOI state-to-state migration files stateinflow/stateoutflow, filing years 2017–18 through 2022–23 |
| Metro corridors and metro gross/net totals | IRS SOI county-to-county migration files countyinflow/countyoutflow, same years |
| Population and components of change (births, deaths, international, domestic) | Census Bureau Population Estimates Program co-est2025-alldata (2020–25), co-est2020-alldata (2010–20), co-est00int-tot (2000–10) |
| State peak population back to 1910 | Census Bureau decennial census (2020 historical population change table) population-change-data-table |
| County-to-metro mapping | OMB/Census 2023 CBSA delineation file list1_2023 |
Map geometry is the U.S. Census Bureau cartographic boundary via us-atlas, drawn in an Albers equal-area projection.
What counts as a "mover"
The IRS compares the address on each year's tax return with the prior year's return. A mover is an exemption (roughly, a person) on a return whose address changed between filing-year pairs. E.g. "2022–23" means returns filed in 2022 matched against 2023. This is a record of realized address changes, not searches or intentions, but it is not a census of everyone: people who don't file (some students, some retirees, the lowest incomes) and unmatched returns are not counted. Exemption counts approximate people imperfectly.
Transformations
- National and state figures use the state-to-state files, which are essentially complete at that level. Metro figures are aggregated from county-to-county files using 2023 CBSA (metropolitan statistical area) definitions; metro gross and net totals come from the IRS per-county summary rows, which include suppressed corridors.
- Corridor lists undercount by design. The IRS suppresses any county pair with fewer than 20 returns, folding it into "other flows". Listed metro corridors therefore cover only part of a metro's gross flows. Each metro page states its coverage share. The two IRS publications also differ slightly: state-file totals run about 1% above summed county summary rows (records not allocable to a county).
- Geography: all 50 states plus Washington, D.C.; Alaska and Hawaii are drawn as insets below the Southwest, as on standard U.S. maps. Puerto Rico and the territories are absent from the IRS migration files and can't be included. "Rest of [state]" entries cover a state's counties outside any metropolitan statistical area. Connecticut switched from counties to planning regions in the 2021–22 files; CT metros have corridor data from then on.
- Population: 2000–2025 series splice three Census estimate vintages; components of change cover 2011–2025. State peak population checks every decennial census back to 1910 at ten-year intervals, so a between-census peak can be missed. Metro series begin in 2000.
- Income ("wealth migration"): the same IRS files report each flow's aggregate adjusted gross income (AGI) alongside the people counts, and the wealth-migration figures surface it as reported. Three things to keep in mind: dollars are nominal (not inflation-adjusted, so cross-year comparisons mix real change with inflation); household averages divide aggregate AGI by returns, not people; and AGI measures the income movers report, not their net worth. "Wealth migration" is the common name for an income flow. State figures use the state files; metro totals use the complete per-county summary rows, with observed within-metro moves subtracted the same way as the people totals. The 2022–23 return-matching change (below) shifts AGI levels too.
Known breaks in the series
- 2018–19 — IRS changed county-level disclosure handling starting with the 2018–19 files. This affects metro figures (built from the county files); national and state figures come from the state files.
- 2022–23 — IRS adopted a new return-matching method for 2022–23, including roughly 5% more returns. Affects every level of the series.
- Filing years before 2017–18 are excluded: the 2013–2017 files carry documented processing changes (an overcount, two undercounts, and a late-filer double-count) that produce artificial jumps at metro level.
Years carrying a break are marked † on the map's year control. Treat year-over-year changes that cross a break with caution.
Update cadence
The IRS publishes migration files roughly two years behind — the current series ends at 2022–23, and the 2023–24 files will be incorporated when released. Census population estimates run through mid-2025.
Citing this tool
Shilo, "Where America Moves" (2026). Derived from IRS Statistics of Income migration data and U.S. Census Bureau population estimates. https://shilo.ai/tools/where-america-moves.
The underlying federal data are public domain. Our derived tables and pages may be cited or reproduced with attribution and a link. If you spot an error, please tell us.
Data retrieved 2026-08-09; pages last built 2026-08-10.