New + Found closes on Mansion House redevelopment financing, prepares to break ground on $195 Million redevelopment project in Downtown St. Louis.
New + Found closes on Mansion House redevelopment financing, prepares to break ground on $195 Million redevelopment project in Downtown St. Louis.
Project will restore the historic midcentury landmark overlooking the Gateway Arch, delivering modern residential units by 2027.
ST. LOUIS, MO (September 29, 2025)—New + Found, the St. Louis–based development firm behind City Foundry, closed Friday, September 26 on the financing to redevelop the Mansion House complex at 300 N. Fourth St. in Downtown St. Louis. The $195 million redevelopment will restore the apartment building overlooking the Gateway Arch, delivering fully modernized residential units by 2027. It represents one of the largest residential investments in Downtown in decades.
The project will breathe new life into a beloved local landmark listed on the National Register of Historic Places. Adjacent to the Arch grounds, it will preserve the property’s iconic midcentury design while introducing modern finishes and shared amenities with sweeping views of the Arch and Mississippi River. Planned renovations include updated unit interiors with in-unit washers and dryers, refreshed common areas, upgraded mechanical and utility systems, new amenity spaces such as a dog run and fitness facility, and enhancements to the promenade. A highlight of the project will be a fully reimagined rooftop pool and amenity deck offering panoramic skyline views.
The 29-story tower will retain all 415 apartments, including 130 studios, 207 one-bedrooms, and 78 two-bedrooms. Lawrence Group is the project’s architecture firm, and PARIC will serve as general contractor.
“New + Found has been based Downtown for more than three decades, and our strategy is to strengthen the city’s core through long-term reinvestment,” said Steve Smith, Founder and CEO of New + Found. “Mansion House continues that approach by preserving a significant architectural landmark and modernizing it to meet current housing demand, ensuring it remains a vital asset for Downtown’s future.”
The redevelopment is backed by a $58.87 million investment from Salt Lake City–based Catalyst Opportunity Funds and received a HUD loan serviced by Gershman. Greater St. Louis, Inc. currently coordinates the Arch to Park Equity Fund, which provided gap financing for the project. Construction is scheduled to begin in October and will be completed by June 2027, with leasing opportunities opening in spring 2027.
The majority of units will be priced affordably to households earning under 80% of Area Median Income (AMI), a key feature of the project, with rents expected to start at $1,100 per month. New + Found expects strong interest and encourages prospective tenants to explore leasing opportunities beginning in early 2027.
“Our investment in Mansion House reflects a strategic commitment to financing projects that preserve affordable and workforce housing, and drive long-term value creation,” said Kristian Peterson, Managing Partner at Catalyst . “By leveraging a HUD loan and federal and state historic tax credits, this redevelopment demonstrates how public and private capital can work together to stabilize and strengthen core urban districts.”
“Delivering a project of this scale requires careful sequencing and a high degree of coordination,” said Greg Trost, Associate Principal at Lawrence Group. “We are focused on maintaining the integrity of the building’s original design while upgrading its infrastructure and systems to meet modern standards. Mansion House will be a model for how historic buildings can be adapted for today’s residential market.”
Downtown Momentum
City leaders emphasize that Mansion House adds to the palpable momentum in Downtown St. Louis.
“The redevelopment of iconic St. Louis buildings like Mansion House is vital to building the future of Downtown St. Louis, and this investment shows the confidence developers have in our city,” said Mayor Cara Spencer. “This project will activate a key property near the Arch grounds and provide new opportunities for residents to live in the heart of St. Louis.”
“Mansion House is a significant property on the edge of the Arch grounds, and its redevelopment demonstrates a commitment to Downtown’s future,” said 8th Ward Alderwoman Jami Cox Antwi. “This project supports our goals for housing diversity, neighborhood activation, and sustainable reinvestment in the city’s core.”
“Redevelopment of a landmark like Mansion House shows real confidence in Downtown St. Louis. This project combines historic preservation with modern living, adds vitality to the Arch grounds, and strengthens the momentum we’re building toward a more vibrant and competitive urban core,” said Dustin Allison, Interim CEO of Greater St. Louis, Inc. Greater St. Louis, Inc. currently coordinates the Arch to Park Equity Fund, which provided gap financing for the project.
Preservation as Progress
As a historic property, the redevelopment will use state and federal tax credits to preserve its midcentury character while delivering modern living.
“Our strategy at New + Found is to invest in landmark properties that define the character of St. Louis,” said Smith. “Projects like Mansion House extend the momentum we’ve built at City Foundry by aligning historic preservation with modern urban living. Our focus is not just on individual buildings, but on creating connected districts that attract residents and businesses, and create a vibrant community for visitors.”
Since its opening in 1966, Mansion House has stood as one of St. Louis’s earliest examples of International Style architecture—a striking steel-and-glass high-rise constructed alongside the Saarinen-designed Gateway Arch. Over the decades, it has been more than a landmark: a residence with sweeping views, mid-century character, and a defining presence on the Arch’s skyline.
“The Gateway Arch and Mansion House rose together in the 1960s,” added Ryan McClure, Executive Director of Gateway Arch Park Foundation. “Just as Gateway Arch National Park went through its own transformation, we are grateful to New + Found and Catalyst for taking on such an important project in Downtown and next to Gateway Arch National Park. The Mansion House redevelopment will help improve the Arch experience for the 2.5 million St. Louisans and visitors that come to the Park every year.”
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About New + Found
New + Found (“N+F”) is a mission-driven, real estate investment firm that develops buildings, communities, and relationships to unlock potential in the overlooked and undervalued. Since 2000, N+F has utilized a mix of private equity, various debt facilities, public incentives, and creative capital solutions to revitalize and reimagine neighborhoods. Since its inception, the team’s management has completed over $900 million in impact related and partner-driven real estate investments within the urban placemaking and build-to-suit net lease sectors.
About Lawrence Group
Lawrence Group is a nationally recognized design firm based in St. Louis with deep roots in architecture, interior design, landscape architecture, master planning, graphic design, and furniture procurement. Known for its creative vision, client-centric approach, and commitment to community, Lawrence Group serves a broad range of markets including multi-family housing, hospitality, workplace, retail, education, senior living, healthcare, and more. With every project, the team aims to deliver design excellence that is sensitive to history, context, and sustainable innovation.
About Catalyst
Catalyst is a double bottom-line private equity firm focused on transformative real estate investments in high potential, but historically underserved U.S. markets. With over $1.3b worth of total real estate across the US, Catalyst invests in impactful, market-rate return oriented development projects led by community-driven, diverse developers, with a primary focus on workforce affordable housing. In addition to providing new, affordable housing units, Catalyst works to facilitate an influx of community services tailored to the needs of each investment community, including preventative healthcare, workforce training and healthy, nutritious food. Institutional investment expertise, relationships with qualified sponsors in high-growth secondary markets, as well as significant experience in the structuring of creative capital stacks give Catalyst a competitive advantage in delivering long-term value creation to investors, as well as positive outcomes within communities.
About PARIC
PARIC focuses on building excellence while also building answers to the special challenges impacting their customers’ operations. With teams in St. Louis, Kansas City and throughout the Midwest, PARIC’s teams routinely deliver for clients within the historic renovation, multi-family, industrial, senior living, healthcare, academic and hospitality markets.