Horn Williamson Marks 10th Anniversary With Move to New Center City Office at One Commerce Square

PHILADELPHIA, Dec. 1, 2025 /PRNewswire/ -- Horn Williamson is pleased to announce the relocation of its Philadelphia office to the full 32nd floor of One Commerce Square, a premier Class-A tower in Philadelphia's Central Business District. Designed by I.M. Pei & Partners, One Commerce Square provides the modern environment needed to support the firm's ongoing growth. The firm's move from its former two-suite office at 2 Penn Center to a customized full floor at One Commerce Square brings the entire Philadelphia team together and enhances collaboration across its three core practice groups: residential construction, commercial construction and community association law.

Horn Williamson worked with Stantec Architecture as architect of record and D&R Construction to deliver a modern workspace to support the firm's continued growth and its expanding Philadelphia team. Arcon Consulting, serving as the owner's representative, collaborated closely with the firm on the suite's design and finish selections, ensuring the space reflects Horn Williamson's functional and aesthetic goals. Commerce Square, owned and managed by Brandywine Realty Trust, provides Horn Williamson with access to an amenity-rich environment including fitness facilities, co-working areas, onsite dining, and a spacious open-air courtyard, all steps from 30th Street Station, Suburban Station, major highways and onsite covered parking.

The move represents a major milestone in Horn Williamson's decade-long expansion and aligns with its 10th anniversary. Established by Jennifer Horn with Carter Williamson in 2015, this WBENC-certified firm has expanded from a two-attorney office into a 25-attorney practice serving clients throughout the Mid-Atlantic. In just the past year, the firm has added several new attorneys and opened its Delaware office under the leadership of new partner, Patrick Costello.

"This move feels like the natural next step in our firm's story," said Horn. "When we started Horn Williamson in 2015, we expected growth but did not anticipate growing into a 25-attorney practice across multiple states and practice areas in just ten years. Bringing our team together at Commerce Square gives us the room and flexibility we need to work more efficiently and continue supporting our clients as their needs evolve."

"This move isn't about square feet—it's about growth. It reflects the momentum we've been building and maintains the firmwide expansion already underway," said Managing Partner Ryan Lockman. "We're building the infrastructure that broadens our capabilities, scales our practice groups and deepens our investment in what matters most—our people."

Horn Williamson's continued expansion reflects its long-term commitment to building a collaborative and inclusive environment that supports meaningful professional growth. With its new Philadelphia headquarters and expanding regional presence, the firm continues to invest in the people, practices, and resources that strengthen its ability to serve its clients and sustain long-term success.

About Horn Williamson LLC
Horn Williamson LLC is a Philadelphia-based law firm focused on construction, real estate and commercial litigation. The firm represents property owners, businesses and individuals in disputes involving construction defects, contracts and consumer protection claims. Founded by Jennifer Horn, Horn Williamson is recognized for its deep knowledge of construction law and its commitment to achieving just results for clients.

Media Contact: 

Olivia Paris-Kornilowicz
Marketing Manager
Horn Williamson LLC
215.995.6839
[email protected]

SOURCE Horn Williamson LLC