Baltimore is 64% larger than Boston.
Area: 212 km2 calculated
Baltimore is the largest city in the U.S. state of Maryland and the 26th-most populous city in the country. It is located in the central area of the state along the tidal portion of the Patapsco River, an arm of the Chesapeake Bay. Wikipedia
Area: 129 km2 calculated
Boston is the capital and largest city of the Commonwealth of Massachusetts in the United States. Boston also serves as county seat of Suffolk County. Wikipedia