Project Overview

The Microsoft Castroville Campus is a multi-site, multi-building Azure data center cluster spanning approximately 1,451 acres in Medina County, Texas, approximately 27 miles west of downtown San Antonio.

As part of Microsoft's Azure South Central US Region & colocation facilities, the data center space is rented to third-party enterprises that support cloud computing, AI inference, and enterprise software services across the US South Central geography.

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The Castroville cluster now comprises approximately six confirmed buildings across four addresses, with a total confirmed investment of over USD 2.19 billion across permitted and under-construction projects as of April 2026.

Active construction sites include the FM 1957 campus (SAT80, SAT81 operational; SAT82 under construction), the FM 471 North site (SAT82 second filing, groundbreaking scheduled in August 2026), the US Highway 90 West campus (SAT89 and SAT90), and further buildings on County Road 381. Microsoft owns land on all four sites.

Castroville Campus Data Center Address

Technical Specifications

Project Background

The first Castroville-area facility was built in Medina County in the years following 2005. By 2015, Microsoft had built at least two data centers in the San Antonio area for USD 90 million each. The company expands its presence by adding facilities at Wiseman Boulevard, Lambda Drive, Westover Link, Rogers Road, and the Texas Research Park in Bexar County.

The Texas Research Park site (SAT14) is planned for up to 1 million square feet across 158 acres, with an investment of up to USD 1 billion. Microsoft announced SAT80 and SAT81 in July 2023. These are two colocation buildings, each exceeding 106,000 square feet on 206 acres at Potranco Road and FM 471 near Castroville, at a combined cost of USD 230 million.

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Construction began in late 2023, and the buildings came online in Q3 2024. The site was selected for flat terrain, grid access, and proximity to fiber and road infrastructure.

In July 2024, Microsoft filed a permit with the Texas Department of Licensing and Regulation for a third building at the FM 1957 address, SAT82, at a cost of USD 482.6 million and 244,676 square feet, with construction targeted from April 2026 to February 2028.

In January 2026, Microsoft filed a second SAT82 application at a different address, 3580 FM 471 North, for an approximately 195,670-square-foot facility at a cost of USD 400 million, with groundbreaking scheduled on August 13, 2026, and completion by July 2028.

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In March 2025, Microsoft filed for two further buildings, namely, SAT89 and SAT90, at 2995 US Highway 90 West, west of Castroville. It is a USD 765 million, 489,400-square-foot project, designed by WSP. Construction began in June 2025, with completion targeted for July 2027.

Additional buildings have also been filed on County Road 381. By December 2025, Microsoft owned approximately 1,451 acres in Medina County, up from its earlier 1,112-acre holding, indicating ongoing land acquisition to support further expansion.

Stakeholders Details

Castroville Campus Data Center Cost & Investment Details

Project Scope

The following is the project scope of the Castroville Campus:

• Design & Structure: The campus is engineered by WSP for Tier II reliability, spotlighting hyperscale infrastructure optimized for Azure cloud services, AI workloads, and redundant power/fiber connectivity.
  

• Technical Specification: Provides scalable, low-latency computing resources leveraging San Antonio's grid, supporting enterprise redundancy and high-density server deployments.
  

• Power Infrastructure: The campus is furnished with advanced substations and backup systems to handle hyperscale power demands, ensuring uptime for critical operations.
  

• Cooling Systems: Incorporates energy-efficient liquid and air cooling technologies tailored for high-density racks, aligning with Microsoft's sustainability goals.
  

• Connectivity Hub: Integrates multiple fiber providers for diverse, low-latency network access, positioning the campus as a regional interconnection point.

Project Timeline

Castroville Campus Data Center Latest News

According to a January 2026 filing with the Texas Department of Licensing and Regulation (TDLR), Microsoft plans to develop another USD 400 million data center facility on the west side of San Antonio. It is in the quaint town of Castroville, with a population of over 3,000.

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The data center facility, SAT82, is located at 3580 FM 471 N and spans approximately 195,670 square feet. Construction is expected to start in August 2026 and be operational by 2028.

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According to TDLR, SAT 82 joins other Medina County Data Centers, including SAT 80, SAT 81, SAT 89/90, and another SAT 82, but with a different address.

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Previously, Microsoft filed another data center, named SAT 82, in July 2024, at a different location. It was located at 18844 Farm-to-Market Road. The developer said the data center would span 244,675 sq ft (22,730 sqm), with construction starting in April 2026 and the project scheduled for completion in early 2028. That data center was estimated to cost Microsoft USD 482.6 million.

Benefits

The following are the benefits of the project in points:

• Boost Infrastructure: Using San Antonio's reliable power grid and fiber networks for low-latency, scalable cloud services, positioning Castroville as a key data center node, overall, boosting the infrastructure.
  

• Technological Advancements: Supports Microsoft's Azure growth for AI and hyperscale workloads with nearly 500,000 sq ft of Tier II facilities, ensuring redundancy and future-proofing through 2028.
  

• Reduce risk of single substation: Distributing buildings across multiple grid feed points reduces the risk of a single substation outage affecting the full Azure availability zone.
  

• Future expansion: Microsoft's land accumulation to 1,451 acres in Medina County, over twice the 206 acres of the original SAT80/81 site, signals that future expansion beyond currently permitted buildings is anticipated.
  

• Sustainability and Reliability: Incorporates efficient designs by WSP for energy optimization, promoting long-term operational resilience amongst rising digital demands.

Conclusion

The Microsoft Castroville Campus is a multi-site data center, spanning approximately 1,451 acres in Medina County, Texas. It is a strategic expansion of the data center infrastructure in Texas, boosting cloud computing & AI workloads.

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Located along US Highway 90 W in Medina County, the campus leverages San Antonio's robust power grid and fiber connectivity to ensure low-latency performance. The development not only boosts regional redundancy but also transforms Castroville's economy, creating hundreds of construction and operational jobs while positioning Medina County as an emerging data center node.  

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As the project advances, it embodies how hyperscalers are reshaping rural landscapes into tech hubs, generating long-term economic vitality and infrastructure innovation for the region. All together, the investment positions Texas as a premier data center corridor, promising sustained growth in the digital economy.

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