Why Montgomery County is a market
Montgomery County is the Maryland side of the Washington metro, and its demand base is unlike anywhere else we cover. Federal agencies and their contractors, the biomedical corridor around the National Institutes of Health in Bethesda, a very large hospital system, financial services and a dense professional middle market. That is an enterprise customer base with real compliance requirements and a reason to keep certain workloads close to home.
It is also the other side of the Potomac from Data Center Alley, and that distinction is the point of this page rather than a technicality. A buyer who asked about Ashburn is not asking about Rockville. The jurisdiction is different, the council is different, the utility is different and the economics are different. Northern Virginia is where you go for scale and interconnection. Montgomery County is where you go when something needs to be near people who work in Bethesda.
The distance is small enough to be useful in both directions. Ashburn is roughly thirty miles from Rockville, so a Montgomery County site works as a second location for an organization whose primary hall is in Loudoun without adding meaningful latency, while sitting in a different jurisdiction with a different power supply.
What this county does not have is merchant campus supply. Read the permit record below before you assume otherwise.
What the public permit record actually shows, and it is not what you might expect
Thirty two filings across twenty three distinct sites, from two separate registers, and every one carries its own public record. Twenty five are county building permits on the open data portal. Seven arrived on 14 September from the federal air register and are a different kind of evidence: they are buildings that hold an air permit and operate, so they carry no filing date at all. What the record mostly describes, though, is not new construction. It is tenants growing inside space they already occupy, and established buildings that have been running for years.
The clearest example runs across two of them. A building on Medical Center Drive in Rockville filed to add a fourth row of server racks to its east data center in November 2024, and the same address filed for related interior work the year before. The locations for those racks were designed into the building when it was constructed in 2012. That is a single occupier expanding twice inside a room that was planned for it, which is a genuinely useful signal for a broker: an organization adding its fourth rack row is an organization that will eventually run out of room.
Three things about this record have to travel with it. The newest dated filing is from November 2024, so nothing here supports a claim about current activity, and the seven air rows carry no date at all rather than a recent one. Not one of the thirty two names an operator we can identify, because the permits are filed by contractors and building owners rather than by colocation providers, and the air rows name occupiers like Verizon, Kaiser Permanente, Gannett and General Electric rather than anyone who would sell you space. And one of them is a decommissioning: the Exelon data center on Westlake Drive in Bethesda, closing in July 2023. That belongs on the page. Leaving it out to make the market look busier is the kind of omission that gets found on a call.
Montgomery County building permits in Bethesda, Silver Spring, Rockville and Germantown. Every figure below is a count of filings we collected ourselves, and every row links to the record it came from.
| Measure | Figure | What it means |
|---|---|---|
| Filings we track | 35 | Deduplicated. Across 2 sources, January 2003 to November 2024 |
| Tenant fit-out filings | 11 | A customer is landing in a named building. The strongest signal in the set |
| Distinct addresses | 23 | Separate sites in the record, not separate buildings |
| Largest floor area filed | 70,423 SF | One permit, not a campus total. Floor area is published far more often than capacity |
| Operators we can name | None | Every filing names an engineer, a builder or a holding company |
| Filings with no date published | 10 | The source publishes the facility, not the filing date |
The most recent filings on the record
Collected from Montgomery County, Maryland commercial permits and EPA ECHO air facility records for Maryland. A permit or air-register entry documents a site or proposed work. It does not establish current construction or available space, and no public filing anywhere discloses what is contractible at a named building. That answer comes from an operator call, which is the part we do by hand. See how we verify capacity.
Three do. The permit layer is the largest of the three and the most checkable, because every filing links to its own public record, on the county's open data portal for the building permits and on the federal air register for the operating buildings. It is also the oldest: nothing in it is from the last twelve months, and seven of its rows carry no date at all. The interconnection layer is small but real and comes from PeeringDB, which the network operators maintain themselves, so every row links to the building's own public entry. The announced layer is here and is one project. The fourth is not here at all: our verified facility inventory does not extend to this county, so there is no building count on this page and no zero standing in for one. See how we verify capacity for what each collection proves.
Who is actually plugged in across Montgomery County, Maryland
A building existing and a building being connected are different facts, and only one of them decides whether your traffic can get where it needs to go cheaply. These figures come from PeeringDB, which the network operators themselves maintain, so every row below links to the building's own public entry.
| Measure | Figure | What it means |
|---|---|---|
| Buildings listed | 5 | Registered in PeeringDB across Montgomery County, Maryland, by 4 operators |
| Buildings with a network present | 3 | 2 carry no network presence, which usually means single tenant or simply unregistered |
| Network presences | 17 | Counted per building, so a carrier in three buildings counts three times |
| Internet exchange presences | 3 | Where you can reach many networks through one port instead of many cross-connects |
| Carrier presences | 0 | The physical transport choice you can buy without leaving the building |
| In the densest building | 71% | Databridge Sites Silver Spring holds 12 of the market's network presences |
The most connected buildings here
| Networks | Building | Operator | Exchanges | Carriers |
|---|---|---|---|---|
| 12 | Databridge Sites Silver Spring | DataBridge Sites | 2 | 0 |
| 4 | Atlantech Online - Rockville, MD | Atlantech Online, Inc. | 1 | 0 |
| 1 | Atlantech Online - Silver Spring, MD | Atlantech Online, Inc. | 0 | 0 |
From PeeringDB, which is maintained by the network operators present in these buildings rather than by the landlords, which is what makes it worth more than a directory. Two limits. Entries are voluntary, so a building showing no networks may be single tenant or may simply never have registered. And a network being present says nothing about whether the building has space, power or a price for you: that is still a call.
What has been announced in Montgomery County, Maryland
Announcements are not filings. Nobody has to build what they announce, the figure is the one the developer chose to publish, and the date moves. They are here because megawatts are what a requirement is measured in, and because the size of what is coming changes who will take your call. Every figure below links to a published report that states it, and was checked against at least one other independent report before it was written down.
| Capacity | Operator | Project | What was announced |
|---|---|---|---|
| 360 MW | Atmosphere Data Centers | Dickerson Generating Station, northern Montgomery County | The site is a retired coal fired power plant on the Potomac in the far north of the county, which is the only reason a project of this size is being proposed in Montgomery County at all: the grid connection is already there. The history matters because the plan has grown. In 2024 Terra Energy applied to build two data center buildings and a utility scale battery installation on the site, and the county Planning Board approved that. In May 2026 the application was re-filed by Atmosphere Data Centers with five buildings of about 226,850 square feet each on 170 acres. The two capacity figures in circulation both attach to that five building plan: 360 MW in trade reporting, and 300 MW of scalable power in Atmosphere's own description of the site. Water is a live issue alongside power. Atmosphere has applied for a permit to draw up to two million gallons a day from the Potomac on peak days, while putting average cooling use at about 69,300 gallons a day. A county public hearing on the updated plan was set for 12 and 13 November 2026. Campus total across the five buildings in the re-filed plan, as reported. The developer's own description of the site says 300 MW, and the row records both rather than picking one |
One announced project, and it is not settled. Montgomery County has been debating how to regulate data centers through 2026, with competing proposals in front of the council, and on 28 July 2026 an 18-month moratorium on new data center approvals. Atmosphere dropped its legal challenge to the earlier pause as moot. Treat the schedule and the size of this campus as open questions rather than as a plan until the county settles its rules. There is a more useful point for a buyer underneath all of that. The Dickerson site is one end of this county, and it is not the market the rest of this page describes. The colocation that exists in Montgomery County today is enterprise scale, inside offices and medical buildings in Rockville, Bethesda and Silver Spring, and none of it depends on what happens at Dickerson. Read the reporting.
Announced capacity is collected by hand from trade reporting and company statements, and each figure links to the report it came from. It is kept apart from the permit record above and never added to it: one is a document a jurisdiction issued, the other is a plan a company published. Neither is availability.
Buying power here is not the same as buying it across the river
Montgomery County is mostly Potomac Electric Power Company territory, part of Exelon, though BGE and Potomac Edison also serve parts of it. Ask which one serves the building. Maryland regulates retail supply differently from Virginia. Retail choice exists for commercial customers, so an operator may be buying generation on a competitive contract or sitting on standard offer service, and that determines whose price you are being quoted.
The live question here is not the tariff, though. It is the zoning. On 28 July 2026 the county council unanimously passed an 18-month moratorium on data center permits. It also passed a zoning amendment that defines a data center as a site drawing at least 25 MW and bars that class from the county until fuller rules are written. The council's vote replaced the county executive's earlier six-month order. Atmosphere, the Dickerson developer, then dropped its challenge to that order in late August, since the council's vote had made it moot. None of that touches a fit-out inside an existing building, which is what most of this market is. All of it touches anything new at scale.
Ask what the building's committed utility capacity is today and what a step up would require, because in this county the answer is usually constrained by a building that was designed as an office. Then ask what the operator's position is under the moratorium and the permanent rules the county is now writing. An operator here who has not read them is an operator who has not thought about whether their expansion plan survives them.
Where the market actually is
Silver Spring
Where the interconnection is. One building holds the large majority of the county's registered network presences on its own. Three other listings sit in the same town, and two of them share its Prosperity Drive address. If your requirement is network led and it has to be in Maryland rather than Virginia, this is where it starts and it probably ends.
Rockville and the Medical Center Drive corridor
Where the permit record is busiest and where the biomedical demand sits. The filings here are interior fit-outs inside occupied buildings, which tells you the space is enterprise rather than merchant, and one listed interconnected building serves the corridor.
Bethesda and East West Highway
Data rooms inside office towers, several of them in the permit record, and also where the one decommissioning in that record sits. Worth scoping if you need to be near people rather than near networks, and worth asking hard questions about floor loading and cooling in buildings never designed for density.
Dickerson, at the north end
The retired coal plant on the Potomac, and the only place in the county where campus scale is even being discussed. It is forty minutes from Bethesda, the plan is paused by the county's 18-month moratorium, and it is not the market the rest of this page describes.
When Montgomery County is right, and when it is the wrong choice
It is right when proximity is the requirement. If your people are in Bethesda, Rockville or Silver Spring, if you have a federal or biomedical compliance reason to keep a workload in Maryland, or if you want a second site that is close enough to manage from your primary but on a different utility and a different jurisdiction, this county does that well and Northern Virginia does not do it better.
It is the wrong choice if you need scale. The permit record here describes rack rows, not halls. There is no merchant campus operating in this county today, the one proposal for one is paused, and the zoning amendment passed in July 2026 bars any data center of 25 MW or more until new rules are written. A requirement measured in tens of megawatts should be tested in Northern Virginia or in Frederick County first.
It is also the wrong choice if interconnection is the driver. Five listed buildings and seventeen network presences is a working ecosystem for an enterprise requirement and is not competitive with what sits thirty miles southwest. If you need many networks in one building, cross the river.
Because most of the good space here is inside buildings designed as offices and medical facilities, ask about floor loading, clear height and slab condition before you talk about density, and ask what the cooling can actually sustain rather than what it is rated for. Ask for committed and energized capacity separately from design capacity. Ask who else is in the room and what their growth plan is, because in a shared enterprise data hall your neighbor's expansion is your constraint. Ask what the operator's read is on the moratorium and the rules that follow it. And if anyone points at the Dickerson project as evidence this market is growing, ask them what has actually been approved.
Pricing context. We found no posted list price in Montgomery County that we would stand behind. A number here comes from a quote. For the nearest rates we track, see Ashburn colocation pricing. The cost estimator gives an illustrative range based on Ashburn. Use it as a reference point, not a local price.