This $615 million project is key to cleaning up the Potomac River ... by a Catholic school and streets on the edge of Old Town Alexandria. In coming months, the drill will go under the river ...

NEW YORK (CNN/Money) -- Potomac, Md. has the highest median household income ... The average American is 35.3 years old, according to census data. The average resident of Potomac is 43.8. They ...