Permits to Fit Out Two Amazon Data Halls in Herndon Arrived the Same Day Amazon Dropped Its Ashburn Plan

On Tuesday, Oct. 20, nine building permit applications reached Fairfax County for 13876 Redskin Drive in Herndon, a building Amazon calls IAD 501. The permits cover the interior of two “data halls,” the large rooms that hold the servers in a data center, along with offices and support space.

The same day, about eight miles to the north, Loudoun County Board Chair Phyllis Randall announced that Amazon would drop its plan for four data centers on the former George Washington University campus in Ashburn. In exchange, Loudoun gets land for an arts center and an indoor sports facility, $5 million for its housing fund, and a fast-tracked rezoning built around homes.

Loudoun holds the world’s largest concentration of data centers. The Herndon campus sits on the Route 28 corridor, across a stream valley from the Floris neighborhood and about a third of a mile from the new Skyview High School. Loudoun’s deal changes nothing about it, because the two sites carry different zoning.

Nine permits ask the county to finish the inside of IAD 501

All nine records appear in Fairfax County’s PLUS permit system as Commercial Addition/Alteration permits, numbered ALTC-2026-02121 through ALTC-2026-02133, with a few numbers skipped. Each carries the same project name: “IAD 501 TI Renaissances Tech Park Building C.” TI stands for tenant improvement, the industry term for building out the inside of a finished shell for the company that will occupy it.

The lead record describes “Occupancy A,” a first phase that “includes second & fifth data hall areas as well as office and associated support spaces.” A temporary wall will separate this phase from later ones and come down once the next phase is complete.

The lead application also records the type of work, a parent permit, a placeholder cost and a review status:

• The permits list a parent permit, meaning the building itself already has its own construction permit on file.
• The type of work is “Interior Alterations,” listed as “Interior Alterations for Owner,” and the structure type is “Industrial Other Than Warehouse.”
• The estimated cost reads $1, a placeholder, so the filings reveal nothing about what Amazon is spending.
• As of Oct. 21, all nine sat at Submitted, the first stage of county review.

The phasing language describes a building that will open in pieces. Amazon would put two data halls and their support space into service while work continues on the rest of the floor plate behind a temporary wall.

Renaissance Technology Park replaced warehouses with a 2.1 million-square-foot plan

IAD 501 is one of the first two buildings at Renaissance Technology Park, roughly 60 acres off Route 28, east of Park Center Road and north of Towerview Road. RP Industrial Owner LLC, an affiliate of Starwood Capital Group, bought the old warehouse complex in June 2019 for $134.1 million and in 2021 proposed replacing it with data centers.

Starwood’s county approval came through a special exception, a permission the zoning ordinance grants only after a public hearing, in this case to build taller than the district normally allows. The record for that case, SE-2021-SU-00017, describes one request: “to allow for an increase in building height.” The Board of Supervisors approved it on July 19, 2022. The overall plan calls for four data center buildings totaling about 2.1 million square feet, a six-acre electrical substation, and support buildings.

Amazon’s name became public in September 2024, through Amazon Data Services’ applications to Virginia’s Department of Environmental Quality for air permits covering the first two buildings, at 13860 and 13876 Redskin Drive. Data Center Dynamics reported that the applications sought 72 stationary generators plus two portable units. Those generators run during power outages and for scheduled testing. The same reporting said the county had approved a building permit for 13860 Redskin Drive in February 2024. Data Center Map lists the two buildings as IAD 500 and IAD 501, part of Amazon Web Services’ US East region in Northern Virginia.

A Starwood affiliate paid $25 million in June 2023 for the former Word of Grace Christian Church property next door, and on Aug. 28 the county issued the permit for a data center there called Renaissance Tech Park Building F. We covered that permit in Another Data Center Just Got the Green Light Near Herndon’s New Skyview High School.

The site carries a Herndon mailing address and a 20171 ZIP code, but it sits outside the Town of Herndon, in Fairfax County’s Sully District. The Floris streets across Horsepen Run fall in the Hunter Mill District.

The campus sits a third of a mile from Skyview High and across a stream valley from Floris

Route 28 and the eastern edge of Washington Dulles International Airport bound the campus on the west. To the east, the wooded Horsepen Run stream valley separates the industrial park from the Floris neighborhood. Skyview High School, which opened this fall at 2949 Education Drive, sits just south of Towerview Road.

Straight-line distances from the edge of the IAD 500 and IAD 501 site, as mapped on OpenStreetMap:

Several homes on the cul-de-sacs off Copper Creek Road and Mountain View Court back onto the stream valley, so their back yards sit closer to the campus than the street figures in the table. Frying Pan Farm Park and Floris Elementary sit farther east, near Centreville Road.

Fairfax’s 2024 data center rules arrived after this campus entered county review

In September 2024 the Board of Supervisors voted 8 to 2 to tighten the county’s data center rules, with Hunter Mill Supervisor Walter Alcorn and Mason Supervisor Andres Jimenez voting no. Northern Virginia Magazine summarized the main standards:

• Data center buildings must sit at least 200 feet from adjacent residential property.
• Backup generators must sit at least 300 feet from residential property lines.
• Data centers must sit at least one mile from any Metro station.
• Developers must submit noise studies before construction and after it.
• All equipment must sit behind a wall or similar screen.

FFXnow reported that projects already in the pipeline before July 2024 could proceed under the earlier rules. Renaissance Technology Park had its special exception approved in 2022, its first building permit in February 2024, and its phase one site plan in county review since May 2024, so it appears to fall on the earlier side of that line.

The county’s staff report on the amendment also notes that the county Noise Ordinance carries exceptions for routine testing of emergency generators. Any change to those exceptions would require a separate amendment to the Noise Ordinance itself.

In Loudoun, Amazon traded a data center plan for housing and a sports complex

Amazon bought George Washington University’s Virginia Science and Technology Campus in Ashburn earlier this year for $427 million. The campus covers about 120 acres. Amazon then filed for an 800,000-square-foot, four-building data center project there, and Supervisor Juli Briskman, whose Algonkian District includes the campus, opposed it from the start. The county’s zoning administrator said this month that data centers are not a permitted primary use on the property, according to the GW Hatchet.

The agreement Randall announced on Oct. 20, which she and Amazon call Project Potomac Promise, does the following, according to Loudoun Now and Data Center Dynamics:

• Amazon withdraws its data center application and gives up any legal fight to build data centers on the site.
• Amazon dedicates about 25 acres, valued at roughly $65 million, for a community arts center and an indoor sports facility.
• Amazon gives $5 million to the county’s housing fund.
• The county fast-tracks a mixed-use rezoning of the remaining land, built mainly around housing, that excludes data centers.

Loudoun Now notes the rezoning could take up to a year and approval is not guaranteed. Loudoun also pushed back a vote, first set for the same meeting, on pausing Board action on data center and substation applications for up to a year. That vote now falls on Nov. 17.

Zoning explains why Herndon kept its data center and Ashburn lost one

Loudoun’s zoning administrator said data centers are not a permitted primary use on the GW campus, so Amazon needed a new approval from a Board whose chair told WJLA, “We knew we don’t want the data centers on that campus.” Renaissance Technology Park sits on land Fairfax’s comprehensive plan designates for industrial uses, its special exception concerned building height, and the Board granted that exception four years ago. Amazon’s air permit applications for the Herndon site described the data centers as consistent with the comprehensive plan’s allowance for “a variety of industrial uses,” as FFXnow reported in 2024.

The Loudoun deal does not signal a change at Renaissance Technology Park. Nothing in the Fairfax record points that way, and the Oct. 20 filings show the work moving forward.

Owners in Floris and western Herndon should check three things

• Sound. A running data center makes steady noise from its cooling equipment and occasional noise from generator testing. The wooded Horsepen Run valley sits between the campus and the closest Floris streets, and that tree cover thins once the leaves drop in November. If a home backs to the stream valley, visit at night and again after the leaves fall before you buy.
• Sightlines. The 2022 special exception exists because these buildings run taller than the district normally allows. Homes nearest the stream valley are the likeliest to see rooflines through bare trees in winter.
• Power. The six-acre substation planned for the campus serves the data centers. Neighborhood outages are a question about the regional grid and the local distribution lines, and distance from a data center does not predict them. Our September post on Building F covers the school power outage figures Fairfax County Public Schools reported at the start of the school year.

Data centers also pay commercial property and business taxes to Fairfax County.

We have written about data center fights closer to Reston too, including CoreSite’s request to change the screening buffer beside the Cocquina cluster and the data center next to the Lake Fairfax Business Center redevelopment.

Watch the permit status, the occupancy permit, and Loudoun’s Nov. 17 vote

• Permit issuance. The nine IAD 501 permits move from Submitted to Issued once county reviewers sign off. Issuance would clear the interior work to begin.
• A Nonresidential Use Permit for IAD 501. That is the county’s occupancy permit for commercial buildings, and it is the clearest public sign that a data hall is ready to run.
• Buildings E and F. Building F’s permit issued in August. Building E, planned at about 406,000 square feet, has an approved site plan but no building permit in the county records we have checked.
• Loudoun’s pause vote on Nov. 17. Loudoun supervisors vote that day on pausing Board action on data center and substation applications for up to 12 months.

We track Fairfax and Herndon development filings every week. If you own near Route 28 or you are weighing a home in Floris, McNair or western Herndon, reach out, and we will pull what is approved, permitted and still on paper around any address you are considering. We do the same for buyers anywhere in Herndon before they write an offer.

See something missing or wrong? Email us at [email protected] and we will check it and update the post.