What King of Prussia's Empty Office Buildings Are Turning Into

For close to 20 years, the office building at 760 Moore Road was an operations center for BNY Mellon. Amazon bought the property from E. Kahn Development in June 2021. According to Montco Today, the building has sat vacant since. On July 16, 2026, Upper Merion's Board of Supervisors voted 4-0, with one supervisor absent, to approve a land-development plan for a 98,500-square-foot facility on the 21.43-acre parcel. The applicant is Amazon Services, LLC. The King of Prussia District calls it a last-mile distribution center replacing a vacant office building.

The July 16 township minutes record the applicant's plan: demolition this fall, construction starting in early 2027, and the building and an adjacent trail open by 2028.

Moore Road is one parcel, but it follows the pattern for Upper Merion's aging office buildings. Each one comes up for its own vote. The approved replacements are delivery operations and rental apartments, not homes for sale. For someone weighing a house in King of Prussia, the office park closest to that house is where change on the street will come from.

A Strong Office Market Leaves Only a Few Weak Buildings

In its 2026 office report summary, the King of Prussia District puts Upper Merion and King of Prussia at roughly 7.8 million square feet of office space and an 11.3% vacancy rate in Q1 2026. That is the lowest rate among the peer markets it lists: Malvern, Wayne, Conshohocken and Exton. Asking rents in the same summary average $29.09 per square foot overall and $34.14 for Class A space, and the District says Class A demand is outperforming the rest. Aerospace and defense firms alone, including Lockheed Martin, Arcfield, Peraton and KBR, occupy about 600,000 square feet and employ more than 3,000 people.

When the newest space is in demand, vacancy collects in older buildings, many of them built for a single large tenant who has since left. The District's own summary describes those underperforming sites being repositioned for residential, logistics and digital-infrastructure uses. The township decides what each of those buildings becomes one site at a time, and the 2026 record shows what those decisions look like.

Three Sites, Three Different Outcomes

Each site went to the board under a different set of concerns. For Moore Road, the issue was traffic. For Vandenberg Road, it was the building's size and who could afford to live there. At 1100 First Avenue, an earlier layout had already been turned back over how it mixed uses.

What the Moore Road Conditions Show About Traffic

For anyone looking at homes near Moore Road, West Valley Forge Road or Route 23, the conditions attached to the Amazon approval matter more than the square footage. According to the July 9 workshop minutes, the applicant plans for tractor-trailers to arrive overnight and delivery drivers to leave during the day. The peaks are listed at 10 to 11:30 a.m. and 7 to 8:30 p.m., which falls outside normal rush hours.

The township and PennDOT added these restrictions:

• No left turns on West Valley Forge Road during posted peak hours
• Tractor-trailers barred from the Route 23 driveway, at PennDOT's request
• Two years of intersection monitoring after the new signal is installed

At the July 9 workshop, Supervisor Greg Philips said he would not vote for the project because of the left-turn access from Route 23. The King of Prussia BID asked that Amazon build trail and sidewalk improvements instead of paying a fee in lieu. At the March 11 Planning Commission meeting, no members of the public commented on the plan.

A buyer looking at a nearby house after 2028 could be living beside a delivery operation built around those exact hours and turn limits. Each one is written into a public document that anyone can read before making an offer.

Vandenberg Road and the Debate Over Size and Affordability

The Greystar project at 720 Vandenberg Road sits on a 6.85-acre site in the King of Prussia Mixed-Use district, known as KPMU. The applicant is GS Vandenberg Owner, LLC. When the Inquirer reported the proposal in September 2025, the plan called for 114 one-bedroom, 87 two-bedroom and four three-bedroom units.

The vote was close. Supervisors Greg Philips and Carole Kenney moved and seconded approval, and Chairperson Tina Garzillo was the third yes. Supervisors Greg Waks and Bill Jenaway voted no. The minutes record Jenaway's objection to the building's size and Waks's question about affordability. Montco Today reported concerns about the building's height.

The split traces back to what the district is for. At a January 2026 workshop, Garzillo described KPMU's purpose as a work-live area with affordable housing and walkable access to jobs and parks. After the vote, Upper Merion Area Spotlight reported Waks saying the township cannot simply require a fixed share of affordable units, and that he would explore zoning incentives for developers who include them voluntarily. In March 2026, the Planning Commission discussed a possible inclusionary-housing bonus aimed at households earning 80% of area median income. The minutes describe it as under consideration.

Any future proposal for an aging office building in KPMU will likely face the same questions about height and affordability. The 3-2 margin shows how close a decision on the next building could be.

The New Housing Is Mostly for Rent

Set the approved projects side by side and they lean toward rentals. Greystar adds 205 apartments. At Valley Forge Presbyterian Church on Town Center Road, a 20-unit affordable apartment conversion broke ground May 28, 2026. Its pastor estimated construction at eight to 10 months, as the Times Herald reported. The largest proposal in the pipeline, at 1100 First Avenue, is also apartments.

New homes for sale come from a different source: townhome communities. The King of Prussia District lists River Trail at Valley Forge, a 119-townhome community, as now selling. The builder lists townhome prices starting at $691,990.

That helps explain an unusual result in the Montgomery County Planning Commission's 2025 Housing Price Report. In 2025, Upper Merion recorded 430 sales at a $594,500 median. Attached homes sold at a median of $664,995, above the $570,000 median for detached homes. The King of Prussia District attributes part of that gap to newer townhome communities, including River Trail and Toll Brothers' Stonebrook at Upper Merion.

Renting a new apartment costs more than the area median as well. Citing CoStar, the District reports 2026 year-to-date average asking rents of $2,159 for one-bedroom and $2,843 for two-bedroom apartments in properties built in 2016 or later. The township's median gross rent is $2,087.

GSK Is Building on Land It Already Owns

The largest employer announcement of the fall doesn't involve a vacant office building at all. The Pennsylvania Department of Community and Economic Development announced on October 9, 2026 that GSK would invest more than $800 million. The plan includes demolition, a commercial-scale biologics factory, an R&D pilot plant, a centralized quality-control laboratory and a manufacturing science and technology hub. Montco Today places the project on GSK's Upper Merion East Campus on River Road.

ENR reports that GSK expects more than 300 permanent jobs over five years, not counting the construction trades. Construction is now expected to start in 2027, a year later than first planned, with full operations targeted for 2030.

Those jobs will arrive in a township where nearly all of the approved new housing is for rent. That leaves the existing detached homes and a few townhome communities as the for-sale supply.

The Fall Market Countywide

Township-level figures for this fall are thin, so the closest current read is the county. In September 2026, Montgomery County had 1,435 active listings, up from 1,212 in August, according to a Bright MLS-based county report. New listings rose from 764 to 877. The median sold price fell from $508,750 to $469,000, and average days on market went from 22 to 24. Across the Philadelphia metro, Bright MLS's September 2026 report shows active listings at month's end 19.6% higher than a year earlier, with a median market time of 16 days.

These are countywide and metro-wide figures covering every home type, not Upper Merion alone. They show more choice across the county this fall. In King of Prussia, though, the office parks are adding rentals and logistics space, so a wider county market doesn't mean more new for-sale homes in the township.

Questions Buyers Ask About the Office Parks

When is the Amazon facility on Moore Road scheduled to open? The applicant's schedule in the township minutes calls for construction starting in early 2027 and the building and trail open by 2028.

Will the Greystar building include affordable units? The approved plan does not include an affordable-housing component, which was one of the objections raised before the 3-2 vote.

Where can I read what the township decided about a specific site? Upper Merion posts its Board of Supervisors and Planning Commission agendas and minutes on the township website. The traffic and design conditions for each site are recorded there.

If you're looking at a home near Moore Road, Vandenberg Road, First Avenue or River Road, Ainlay Dixon can go through what has been approved nearby and what it could mean for the house you're considering. Start with an instant home valuation, and then we can talk about the street itself.