Third-party notices
The notices data providers require, then the open-source code this site is built with and the licence each part is used under. Every data source is cited on the pages that show it and listed on the sources page.
Data notices
Notices the providers of data shown on this site ask every user of their data to display:
- This product uses the Bureau of Economic Analysis (BEA) Data API but is not endorsed or certified by BEA. (BEA Data API (Regional dataset), BEA county personal income, yearly, BEA state personal income, quarterly)
- This product uses the Census Bureau Data API but is not endorsed or certified by the Census Bureau. (American Community Survey, 5-year estimates, Quarterly Workforce Indicators)
- This product uses FHFA data but is neither endorsed nor certified by FHFA. (source)
- Data Provided by Zillow Group. (source)
Arc UI (uiarc.dev), free tier
Research methods also use the official free Comparison Table and Timeline registry components. Site extensions provide equal emphasis for both research lenses, rich numerical cells, and archive dates without invented clock times.
Files under src/components/arc/ were installed from the Arc UI registry (https://uiarc.dev/r/<name>.json) with the shadcn CLI on 2026-10-09: arc-foundation (with arc-motion-tokens) and button; popover, scroll-area, segmented-control, alert and empty-state on 2026-10-11 (their registry JSON was written to the same paths the CLI uses; popover.tsx, scroll-area.tsx and empty-state.tsx carry site patches, checked by scripts/verify-arc-patches.mjs). morph-select was installed from the official free registry on 2026-10-13. Its source and license are retained under src/components/arc/morph-select/; a site patch keeps the growing menu within the viewport. card was installed from the official free registry on 2026-10-14; its source and license are retained under src/components/arc/card/. The site draws it only as a tile whose whole area is one link (src/components/ui/link-card.tsx, a destination tile, and src/components/ui/step-card.tsx, the "On this page" steps). card.tsx carries site patches, checked by scripts/verify-arc-patches.mjs: the title may be a node, and its element may be chosen (headingLevel, default h3 as in Arc), so a list of anchor links does not add headings; and the quick look (details, its morph, the Radix dialog and the close icon) is removed, because the site never passes details and the dialog was about 15 KB of script (gzip) on every page that draws a tile.
badge was installed from the official free registry on 2026-10-15 under src/components/arc/badge/ (the license below covers it, as for alert). The site draws it only as the "Our research" label (src/components/ui/research-tag.tsx). Site patches, checked by scripts/verify-arc-patches.mjs: Arc's label morph (a rolling text swap and a width spring that watches the label's size, which made it a client component) is removed, so the badge is a plain span drawn on the server with no script, and its hover tint is removed, because a fixed label must not look like a control.
stats-band (a block) was installed from the official free registry on 2026-10-14 under src/components/arc/blocks/stats-band/, with its license. The site draws it as the headline numbers of "Why these counties" and of the data-centers hero (src/components/ui/stat-band.tsx), with no chart or sparkline: none of those numbers has a published series to draw. Arc's sample numbers, its docs-page preview and its visuals (a trend, an uptime strip, a histogram and a dotted world map, with the world-map data file) are removed, so an unsourced chart cannot be drawn. Site patches, checked by scripts/verify-arc-patches.mjs: the figures are an ordered list with each number before its sentence (Arc's description list puts the label first, so a screen reader would hear the sentence before its number); the list carries the accessible name, not a region; the numbers show in server HTML and without JavaScript, and the band is hidden and counted up only after hydration, only when it is still below the fold and motion is allowed; count turns the count-up on (the site leaves it off: a count-up shows values the research never published on the way to the real one); a figure that cannot be counted exactly may be given as text. The figures themselves are the page's own formatted text, read back by src/lib/figure-stat.ts only when that reproduces it exactly (scripts/test_counties_figures.mjs).
src/styles/arc-foundation.css is generated from src/components/arc/foundation.css by scripts/scope-arc-foundation.mjs, which limits Arc's tokens and focus rules to elements inside class="arc".
The registry files carry no license header. The license below is copied from https://uiarc.dev/license (read 2026-10-09; that page is marked "Draft, pending review", and it says free components are MIT and Pro components are under a separate paid license). No Pro item is used.
MIT License Copyright (c) 2026 Elia Kuratli Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
These notices are published with the site at /notices (linked from the footer), because the minified code of every package below is sent to browsers.
Radix UI
Packages: @radix-ui/react-popover, @radix-ui/react-dialog and their @radix-ui/* dependencies.
Used by Arc's popover (the card used the dialog until its quick look was removed, 2026-10-15; the package stays in package.json and can be dropped when the lockfile is next regenerated). MIT; the text below is the LICENSE file of @radix-ui/react-popover 1.2.0 (read from the npm package on 2026-10-11). @radix-ui/react-dialog 1.2.0 carries a byte-identical file (compared on 2026-10-14) and pins the same @radix-ui/* versions as the popover.
MIT License Copyright (c) 2022 WorkOS Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
The popover also brings in @floating-ui/* (MIT, "Copyright (c) 2021-present Floating UI contributors"), react-remove-scroll and react-style-singleton (MIT, "Copyright (c) 2017 Anton Korzunov") and aria-hidden (MIT, "Copyright (c) 2017 Anton Korzunov"); each package carries its own LICENSE file in node_modules.
motion
Packages: motion, framer-motion, motion-dom, motion-utils.
Used by Arc's button and animation presets. MIT; the text below is the LICENSE.md of motion 14.1.0. framer-motion carries the same licence with "Copyright (c) 2018 Framer B.V.".
The MIT License (MIT) Copyright (c) 2024 Motion B.V. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
lucide-react
Used by Arc's alert and empty-state for their icons. ISC, with an MIT part for the icons derived from Feather; the text below is the LICENSE file of lucide-react 1.55.0 (read from the npm package on 2026-10-11).
ISC License Copyright (c) 2026 Lucide Icons and Contributors Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. --- The following Lucide icons are derived from the Feather project: airplay, alert-circle, alert-octagon, alert-triangle, aperture, arrow-down-circle, arrow-down-left, arrow-down-right, arrow-down, arrow-left-circle, arrow-left, arrow-right-circle, arrow-right, arrow-up-circle, arrow-up-left, arrow-up-right, arrow-up, at-sign, calendar, cast, check, chevron-down, chevron-left, chevron-right, chevron-up, chevrons-down, chevrons-left, chevrons-right, chevrons-up, circle, clipboard, clock, code, columns, command, compass, corner-down-left, corner-down-right, corner-left-down, corner-left-up, corner-right-down, corner-right-up, corner-up-left, corner-up-right, crosshair, database, divide-circle, divide-square, dollar-sign, download, external-link, feather, frown, hash, headphones, help-circle, info, italic, key, layout, life-buoy, link-2, link, loader, lock, log-in, log-out, maximize, meh, minimize, minimize-2, minus-circle, minus-square, minus, monitor, moon, more-horizontal, more-vertical, move, music, navigation-2, navigation, octagon, pause-circle, percent, plus-circle, plus-square, plus, power, radio, rss, search, server, share, shopping-bag, sidebar, smartphone, smile, square, table-2, tablet, target, terminal, trash-2, trash, triangle, tv, type, upload, x-circle, x-octagon, x-square, x, zoom-in, zoom-out The MIT License (MIT) (for the icons listed above) Copyright (c) 2013-present Cole Bemis Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Picture credits
The archival pictures on the home page, About and the White Paper show the world around the research: nineteenth-century government atlases, charts and census machines. None of them is the client’s own work and none is data of this site. Each is shown in greyscale, and each is a crop or a re-encoding of the work named here. The pictures are taken from open collections, and their licences are the ones those collections state.
- Scribners-1880-Popular-Vote1 (Scribner's 1880 election map by popular vote; Plate 11, Popular Vote, ratio of predominant to total vote, by counties, 1880)Scribner's (Charles Scribner's Sons); Statistical Atlas of the United States, compiled by Fletcher W. Hewes and Henry Gannett from the Tenth Census, 1883 · Scan: Scan found via mappingthenation.com (Commons credit line); the same plate is held by the Library of Congress (Geography and Map Division, g3701gm.gct00009)Licence: Public domain. Source: Wikimedia Commons.Files: crossfade-1.jpg, popvote-1880.jpg
- Total population. Average density, by counties. Based on the returns of the tenth census. 1880. Copyright, 1883, by Charles Scribner's Sons.Gannett, Henry; Hewes, Fletcher W.; United States Census Office (Scribner's Statistical Atlas, Plate 22), 1883 · Scan: David Rumsey Map Collection, David Rumsey Map Center, Stanford Libraries (image 4521.022), via Internet ArchiveLicence: Public domain. Source: Wikimedia Commons.Files: crossfade-2.jpg
- Improved farm land. Ratio to total area, by counties. Based on the returns of the tenth census. 1880. Copyright, 1883, by Charles Scribner's Sons.Gannett, Henry; Hewes, Fletcher W.; United States Census Office (Scribner's Statistical Atlas, Plate 96), 1883 · Scan: David Rumsey Map Collection, David Rumsey Map Center, Stanford Libraries (image 4521.097), via Internet ArchiveLicence: Public domain. Source: Wikimedia Commons.Files: crossfade-3.jpg
- Taxation, per capita, by counties. Based on the returns of the tenth census. 1880. (with) By states, 1880. (with graph) Total taxation, by states, 1880. (with graph) Taxation per capita, by states, 1880. Copyright, 1883, by Charles Scribner's Sons.Gannett, Henry; Hewes, Fletcher W.; United States Census Office (Scribner's Statistical Atlas, Plate 74), 1883 · Scan: David Rumsey Map Collection, David Rumsey Map Center, Stanford Libraries (image 4521.075), via Internet ArchiveLicence: Public domain. Source: Wikimedia Commons.Files: crossfade-4.jpg
- Preliminary Chart of Bull's Bay South Carolina.United States Coast Survey (A. D. Bache, Superintendent; translation by C. O. Boutelle), 1859 · Scan: Geographicus Rare Antique Maps (file provided to Wikimedia Commons by Geographicus)Licence: Public domain. Source: Wikimedia Commons.Files: tide-chart.jpg, coast-survey-bay.jpg, stamp.jpg
- Kennebec and Sheepscot Rivers Maine.United States Coast Survey (A. D. Bache, Superintendent), 1862 · Scan: Geographicus Rare Antique Maps (file provided to Wikimedia Commons by Geographicus)Licence: Public domain. Source: Wikimedia Commons.Files: tide-chart-2.jpg
- Relief Map of the United States. Constructed under the Supervision of Henry Gannett Chief Geographer U.S. Vertical Exaggeration 15 inches to 1 inch horizontal. Copyrighted 1887.Yaggy, Levi Walter (Geographical Chart; constructed under the supervision of Henry Gannett), 1887 · Scan: David Rumsey Map Collection, David Rumsey Map Center, Stanford Libraries (image 10200.023), via Internet ArchiveLicence: Public domain. Source: Wikimedia Commons.Files: relief-map.jpg
- (Statistical Tables) (County, Population and Presidential Election Results).J. A. Caldwell (Caldwell's Illustrated, Historical, Combination Atlas of Clarion Co. Pennsylvania); Rumsey record lists Caldwell, Joseph A.; Cring, Henry; Arms Sr., C.T.; Longdon, F.J.; Goodwin, J.W.; Howden, J.A.; McCloy, T.M.D., 1877 · Scan: David Rumsey Map Collection, David Rumsey Map Center, Stanford Libraries (image 2772.004), via Internet ArchiveLicence: Public domain. Source: Wikimedia Commons.Files: source-table.jpg, source-table-full.jpg
- Scribner's statistical atlas of the United States, showing by graphic methods their present condition and their political, social and industrial development (Plate 6, Supremacy of parties and increase of the popular vote; LOC a40001834-34)Hewes, Fletcher W. (Fletcher Willis); Gannett, Henry, 1883 · Scan: Library of Congress, Geography and Map Division (g3701gm.gct00009)Licence: Public domain. Source: Wikimedia Commons.Files: atlas-plate-1-full.jpg
- Scribner's statistical atlas of the United States, showing by graphic methods their present condition and their political, social and industrial development (Popular vote 1884, pp. 22-23; LOC a40001834-40)Hewes, Fletcher W. (Fletcher Willis); Gannett, Henry, 1883 (atlas; the 1884 map is a later addition to the LOC copy, copyright 1885 on the plate) · Scan: Library of Congress, Geography and Map Division (g3701gm.gct00009)Licence: Public domain. Source: Wikimedia Commons.Files: atlas-plate-2.jpg
- 2018 Ballots being counted in Santa Clara CountyLegoktm, 2018-11-07Licence: CC BY-SA 4.0 (this excerpt is an adaptation, shared under the same licence). Source: Wikimedia Commons.Files: ballots.mp4, ballots-poster.jpg
- 1890 Census Hollerith Electrical Counting Machines Sci Amer (The Hollerith electric tabulating machine being used for the 1890 U.S. Census)Artist not credited; Scientific American, 1890-08-30 · Scan: Scientific American, 30 August 1890 (Commons credit line: via a reproduction at officemuseum.com)Licence: Public domain. Source: Wikimedia Commons.Files: hollerith.jpg