(from Wikipedia) Topologically Integrated Geographic Encoding and Referencing, or TIGER, or TIGER/Line is a format used by the United States Census Bureau to describe land attributes such as roads, buildings, rivers, and lakes, as well as areas such as census tracts. TIGER was developed to support and improve the Bureau’s process of taking the Decennial Census.

TIGER defines geographic areas and features using topology, to represent the relationships between such features on a map. TIGER enables geocoding of street addresses.