Sources and their limits

Checked 2026-09-27 and 2026-09-28.

Virginia DEQ: Air Sites (Daily)

• `https://apps.deq.virginia.gov/arcgis/rest/services/public/EDMA/MapServer/294` ("Air Sites (Daily)"), queried with PLA_DATA_CENTER_YN = 'Y'. DEQ describes the layer as all active DEQ-permitted air facilities, located from 911 addresses or other information confirmed by DEQ staff, and updated daily (see DEQ's Active Air Sites fact sheet).
• Used fields: PLA_REG_NUM (registration number), PLA_NAME, FAC_L_ADDR_1, FAC_L_CITY, FAC_L_ZIP5, AIR_OP_STATUS (Planned, Under Construction, Operating, Temporarily Shutdown), PCL_STATE_DESC (permit class), point geometry.
• On 2026-09-28: 198 sites (43 planned, 1 under construction, 153 operating, 1 temporarily shut down).
• Limit: a data center appears only once it applies for an air permit for its generators. Earlier stages (rezoning, special exception) are county records and not included yet.
• DEQ's data notice (the layer's Data_Disclaimer field) is shown on the site as published.

Virginia DEQ: issued air permits for data centers (snapshot)

• `https://www.deq.virginia.gov/news-info/shortcuts/permits/air/issued-air-permits-for-data-centers`
• The page blocks automated requests (an Akamai 403, even for robots.txt), so it is not fetched by the build. It was opened in a normal browser and its table saved as deq_issued_permits_2026-09-21.tsv (the page's "as of" date): 194 permits for 183 facilities in 19 localities. The saved counts match the page's own.
• It's joined to the Air Sites layer by registration number (the part of the permit number before the dash). All 183 facilities are in the layer. 15 layer sites have no row yet, probably permits still in progress, and the site says so for them.
• Known quirks, handled in build.py: one malformed date ("03/26-2026"), inconsistent program spelling ("Article 6
  • mNSR", "Article 6 mNSR", "Article 6-mNSR"), entries that cover several buildings.

Virginia DEQ: county boundaries

• Layer 157 of the same service: the 133 counties and independent cities (FIPS 510 and up are cities), simplified to about 100 m for point-in-polygon.
• Known disagreement: three sites near the Manassas airport (registration numbers 74118, 74240, 74246) fall in Prince William County by these boundaries (confirmed with DEQ's own server-side spatial query), but DEQ's permit list says Manassas City. The site shows both rather than pick one.

Loudoun County: Loudoun Online Land Applications (LOLA)

• `https://logis.loudoun.gov/gis/rest/services/Projects/LOLA_DATA/MapServer/0`, queried for applications whose name or description mentions "data center" or "datacenter" (508 records on 2026-09-30). Fields requested: PlanNumber, PlanApplicationDate, PlanType, PlanStatus, PlanName, PlanDescription and the parcel outline. The staff-assignment fields (a reviewer's name and email) are never requested.
• pipeline/filings.py keeps land-use applications (legislative applications, rezonings, special exceptions, concept plan amendments, commission permits) and site plans (engineering plans), drops paperwork (bonds, plats, studies, correspondence) and decided applications filed before 2021, and folds "SEE LEGI-... FOR DOCUMENTS" sub-applications into their umbrella: 173 filings on 2026-09-30 (78 in review, 95 approved). Each point is the center of the application's parcel outline; each links to its record on the county's server.
• Personal data: descriptions often end with the reviewing planner's initials, and some name an attorney or an owner; initials and review-session numbers are stripped, descriptions that name someone "on behalf of" an owner are replaced with a pointer to the county record, and one plan name that is a private person's name is withheld.
• Limits: the server is sometimes down (it answers with an HTML error page). The build then keeps the last published filings (site/virginia/data/filings.json), as it does when the data fails its checks (far fewer filings than last time, points outside Loudoun, missing fields). Statuses are the county's; a few old applications still show "In Review" years later.

National Center for Education Statistics: public school locations

• `https://nces.ed.gov/opengis/rest/services/K12_School_Locations/EDGE_GEOCODE_PUBLICSCH_2425/MapServer/0`, queried with STATE = 'VA': 2,159 schools with name, street, city, ZIP and coordinates (2024-25).
• Limit: official names are often short ("Carson Middle", not "Rachel Carson Middle School"). The search matches partial names, and landmark_aliases.json adds common names by NCES school ID.

U.S. Census Bureau: ZIP Code Tabulation Areas

• 2025 Gazetteer (2025_Gaz_zcta_national.zip), internal point of each ZCTA. Virginia is taken as ZIP prefixes 201 and 220-246 (200 and 202-205 are DC; 206-219 are Maryland): 903 ZIP codes.
• Limit: a ZIP code's center can be a few miles from any given home in it; the page says distances are measured from the center, and a school or a pin gives a precise point.

County meeting agendas (civic layer, pipeline/civic.py)

• Granicus agenda RSS, ViewPublisherRSS.php?view_id=N&mode=agendas: Fairfax (video.fairfaxcounty.gov, view 7, Board of Supervisors), Loudoun (loudoun.granicus.com, view 89, Board of Supervisors, Planning Commission and committees; the feed is titled "2024 Archive" but carries 2026 meetings), Prince William (pwcgov.granicus.com, view 23, Board of County Supervisors and joint meetings). Meeting dates come from the item title ("... - Sep 22, 2026"); Fairfax posts every meeting twice (the second copy has Spanish captions), kept once.
• Agendas: Loudoun's link opens an HTML agenda (GeneratedAgendaViewer.php); Prince William's opens an HTML agenda stored on Granicus's S3 bucket. Items are the numbered lines ("7.D.", "VI." then "3."). Fairfax's link forwards to the meeting page on fairfaxcounty.gov, whose agenda is a PDF board package (13 MB for Sept. 15, 2026): not searched; the meetings are listed with a link.
• robots.txt (checked 2026-09-30): all three Granicus hosts answer User-agent: * / Disallow: / (only named search engines are allowed). Following the project rule, the build doesn't fetch them (RESPECT_ROBOTS_TXT), so site/virginia/data/meetings.json is refreshed by hand from pages saved in a browser (python pipeline/civic.py --saved DIR), like DEQ's permit list, until the owner decides otherwise (for example after asking the counties' clerks). The 2026-09-30 file was made that way from 1 feed per county and 7 agendas.
• Item text is shown as the agenda has it, minus presenter/staff names (Prince William's "- Name, Department" and Loudoun's "Project Manager: Name"); check() refuses output with an email address or a staff label.
• Limit: an item is found only if its title says "data center" (or, once county filings are wired in, names a data center case number); items about a data center project that don't say so are missed.
• No Legistar API for these counties: the Legistar client pwcgov is not Prince William County, and fairfaxcounty/loudoun don't exist.

How to take part (data/participation.json)

• Hand-checked on 2026-09-30 from the counties' own pages: Fairfax Clerk Services' "Ways to Provide Public Hearing Testimony"; Loudoun's "About Board of Supervisors Meetings" and "Speaking at Planning Commission Public Hearings"; Prince William's Board of County Supervisors page and its Public Comment Time and Public Hearing FAQs (PDF). Each fact carries its source and checked date. Office phone lines only; no staff names or emails.

Map

• MapLibre GL JS 6.11.2, served from site/vendor/ (BSD-3-Clause; site/vendor/LICENSE).
• Basemap tiles from OpenFreeMap (free, no key, no cookies), positron (light) and dark styles; attribution shown on the map.