Positioned in the heart of downtown St. Charles, Illinois, the professional office/retail building at 12–14 N Riverside Avenue offers a rare opportunity to own a high-visibility asset in one of the region’s most vibrant commercial corridors. Spanning 7,500 square feet across two floors, the property features 20 private offices, a welcoming reception area, a spacious conference room, and four restrooms. The first floor showcases a distinctive interior brick-paved walkway, while the second floor impresses with raised ceilings, exposed timbers, and pyramid-style skylights that flood the space with natural light. Recent capital improvements include a new rooftop HVAC system, an automated fresh air system, and a high-end fire/smoke alarm system. The building also benefits from updated 200 Amp 3-phase electric service and a roof that was recoated and sealed within the last decade. With 51 feet of street frontage and two public parking lots directly across the street, the property ensures ease of access for tenants and visitors alike. Located within walking distance to the downtown core and adjacent to the scenic Fox River, the site is surrounded by a mix of retail, dining, and residential amenities. The area’s demographic profile reveals a strong professional and managerial workforce, high average household incomes exceeding $125,000 within a 1-mile radius, and a stable owner-occupied housing base. This asset is ideal for investors or owner-users seeking a well-maintained, centrally located property with flexible tenant configurations and enduring curb appeal.