County Hall's main six story building, faced in Portland stone and inspired by an Edwardian Baroque style, was designed by British architect Ralph Knott. Its construction, undertaken by Holland, Hannen & Cubitts, began in 1911 and finished in 1922 when it was opened by King George V.
County Hall was the headquarters of the London County Council and Greater London Council. Today, the building houses two hotels, several restaurants and a visitor center.