The Hillsboro Civic Center is a government-built, mixed-use development in downtown Hillsboro. The development includes the city hall of Hillsboro, which is the county seat of Washington County, located west of Portland. Covering six acres, the Civic Center has a total of over 165,000 square feet (15,300 m2) in the complex. The total of six stories for the main structure makes the building the tallest in the city, tied with Tuality Community Hospital. In addition to government offices, the Civic Center includes retail space, public plazas, and residential housing. The complex was built to centralize city government functions under one roof, allowing the city to move many offices from leased space in the county's Public Services Building. Design of the complex began in 2002, with construction beginning in 2003. After completion in 2005, the building was awarded the LEED Gold certification for sustainability, the second city hall in the United States to earn that distinction. Environmentally friendly technologies used include occupancy sensors, ventilation that monitors carbon dioxide levels to determine when to activate, high performance exterior glass to reduce heat loss, and solar panels to generate electricity. Other features of the complex include conference space, public plazas, outdoor fountains, and an auditorium used for city council meetings, among other items.