4601 Fairfax Drive

Ballston

Penzanace purchased the 239,678-square-foot office building from UBS Realty Investors LLC in September 2023 and has filed updated plans with Arlington County for a residential development at the site of the Ballston One office building. The developer received Arlington County Board approval in July 2025 for its 328-unit adaptive reuse of the Ballston One office building at 4601 Fairfax Drive, but the timeline for construction hinges on a federal lease. The Cybersecurity and Infrastructure Security Agency (CISA) currently occupies a significant portion of the 12-story building and is expected to relocate to its new headquarters at the St. Elizabeths campus in Southeast DC — but its lease could theoretically be extended indefinitely. When it gets underway, the project will reuse the existing underground parking garage and deliver studios through two-bedroom-plus-den units, along with 13 two-story loft homes.