01
Now leasing
Suite A/102
1,065 RSF
A Class A workplace within 355 Main, ready for a tenant-defined program.
Inquire about this suiteArmonk, New York · Class A
A building for the work ahead.
355 Main brings considered workspace and sovereign technology together within Armonk Professional Center.
01 / The building
One address. A more complete way to work.
Managed by Sovereign Shells, 355 Main is a focused building and suites experience within Armonk Professional Center—a Sovereign Shells campus encompassing 355 Main and 357 Main.
The environment pairs Class A workplace standards with infrastructure for organizations that value control, privacy, and proximity to their technology. Vatche Simonian's design unites the original 1960s brick building with a two-story glass enclosure and stone-clad elevator tower.
02 / Current inventory
Space with a clear status.
Two suites are now leasing. Occupied space and tenant milestones are shown separately and are not available offers.
02
Now leasing
Suite B/104
1,162 RSF
A Class A workplace designed for focused teams and executive operations.
Inquire about this suite03
Leased to Trucast
Suite C/106 — Trucast
1,060 RSF
An occupied first-floor suite leased to Trucast. This space is not available.
Not current availability
04
Leased
Suite 103 — Northwell Health
3,193 RSF
An occupied first-floor suite. This space is not available.
Not current availability
05
Leased to Alpha School
2nd Level Full-Floor Flagship Suite
7,590 RSF
A tenant milestone for Alpha School, an AI-powered K–8 education platform. This space is not available.
Not current availability
03 / Node 1 · Physical workplace
Accepting qualified interest
Sovereign technology with a physical place to work.
Node 1 pairs tenant-controlled sovereign AI infrastructure with meeting environments, offices, and available suites at 355 Main. It is the physical-workplace counterpart to Node 2 at 357 Main.
NODE_01
Physical workplace
Pair compatible sovereign infrastructure with meeting environments, offices, or an available suite through a qualified engagement.
NODE_02
Campus continuity
Qualified Node 2 clients can pursue connection to compatible physical space through the dark-fiber campus backbone as availability evolves.
NODE_03
Tenant control
Sovereign Shells manages the property context. Nate by Native Agentic independently assesses software, compute, security, and operating requirements before activation.
Node enrollment and suite leasing are separate engagements. Access, carrier design, activation, and pricing remain subject to qualification.
03 / The standard
Assess the room before depending on it.
Nate—the Native Agentic Technical Engineer—is independently operated by Native Agentic. It can diagnose a candidate suite and, where compatible, help bring tenant-owned silicon into an always-on private compute environment.
Local infrastructure
Assessment identifies what power, fiber, cooling, security, and hardware are present and what must change. A listing alone is not proof of readiness.
Tenant custody
Tenants can retain ownership and custody of compatible hardware and data under the terms of the selected engagement.
Operated layer
Nate can operate compatible dedicated silicon continuously, with dedicated IPs where carrier, security, and site conditions permit.
04 / Spatial proof
Matterport capture · Level 2
Walk the captured space. Verify the current facts.
This 3D capture records the Level 2 suite before fit-out. The suite is leased to Alpha School and is not an available offer. The capture is spatial evidence only; confirm present condition, infrastructure, and availability with the responsible property team.
05 / Tenant milestone
Leased · Not available
Alpha School selects 355 Main.
Alpha School, an AI-powered K–8 education platform, leased the 2nd Level Full-Floor Flagship Suite. The space represents a tenant milestone—not current availability.
06 / The campus
355 Main is part of something larger.
355 and 357 Main are sister buildings by architect Vatche Simonian, linked by a private dark-fiber campus backbone. Together, Node 1 and Node 2 create a qualified path from virtual sovereign service to compatible physical space as the campus evolves.