Washington, D.C. is 4.7% larger than St. Louis.
Area: 170 km2 calculated
St. Louis is an independent city and a major United States port in eastern Missouri. The city reaches the western banks of the Mississippi River, which forms Missouri's eastern border with Illinois. At the 2010 census, St. Wikipedia
Area: 178 km2 calculated
Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. Wikipedia