Column Name        Type                 Column Definition 
OBJECTID           int                  Unique identifier for the record
Shape              varchar(20)          Type of shape: point, line, polygon, multipoint, or multipatch
StateFIPS          varchar(2)           Census state FIPS code
CountyFIPS         varchar(3)           Census county FIPS code
Tract              varchar(6)           Census tract code
Block              varchar(4)           Census tabulation block number
CensusKey          varchar(16)          Fifteen or sixteen-digit key that represents: State (2) + County (3) + Tract (6) + Block Group Number (4) + Optional Block Suffix (1). The suffix is used to indicate if any changes were made the to Block Group Number
HousingUnit        int                  Census housing unit count
Population         int                  Census population count
Area               decimal(21,12)        Area of the block in square meters
Perimeter          decimal(19,12)        Perimeter of the block in meters
ShapeWKT           varchar(35000000)    Well-Known Text field
ShapeWKTLength     int                  Well-Known Text field length
Shape_Length       decimal(20,18)        *Length (perimeter) of shape 
Shape_Area         decimal(20,18)        *Area of shape 

* Measurements are in decimal degrees, driven by the original coordinate system.  Not reliable for use.