U.S. States and Counties
GeoDataset names:  States and Counties - Detail States and Detail Counties
U.S. States and Counties represents all fifty states and the District of Columbia, and all of the counties in the United States.  The standard versions are generalized to improve draw performance and be used effectively at a national level.  The detailed versions have boundaries that are consistent with the tract, zip and major road data sets and have boundaries that are good for regional and state level maps. 
States/Dtl_st --  U.S. States
51 polygons, 51 descriptive fields. Defines U.S. states and the District of Columbia.
Fields:
Area -- The area of the state in square miles based on an Albers Equal Area Projection. (Numeric)
State_name -- The state name. (String)
State_fips -- The state FIPS code. (FIPS stands for the United States Federal Information Processing Standards.)  Example:  23 for Maine. (String)
Sub_region -- The subregion of the United States in which a state is located.  Example:  Mid Atl. (String)
State_abbr -- Two-letter postal code for the state name. (String)
Pop1990 -- The population of the state in 1990 based on the US Census. (Numeric)
Pop1997 -- The population of the state in 1997 estimated by Claritas. (Numeric)
Pop90_sqmi -- The 1990 population per square mile for a state. (Number)
Households -- Total number of households. (Number)
Population by race and ethnicity
Males -- Number of males. (Number)
Females -- Number of females. (Number)
White -- Number of people identified as white. (Number)
Black -- Number of people identified as black. (Number)
Ameri_es -- Number of people identified as American Indian, Eskimo, or Aleut. (Number)
Asian_pi -- Number of people identified as Asian or Pacific Islander. (Number)
Other -- Number of people identified as belonging to a race other than white, black, American Indian, or Asian. (Number)
Hispanic -- Number of people of all races identified as being of Hispanic origin. (Number)
Population by age
Age_under5 -- Number of people 0 to 4 years of age. (Numeric)
Age_5_17 -- Number of people 5 to 17 years of age. (Numeric)
Age_18_29 -- Number of people 18 to 29 years of age. (Numeric)
Age_30_49 -- Number of people 30 to 49 years of age. (Numeric)
Age_50_64 -- Number of people 50 to 64 years of age. (Numeric)
Age_65_up -- Number of people 65 years of age and over. (Numeric)
Population by marital status
Nevermarry -- Number of people who have never been married. (Number)
Married -- Number of people who are married. (Number)
Separated -- Number of people who are separated from their spouse. (Number)
Widowed -- Number of people whose spouse died. (Number)
Divorced -- Number of people who are divorced. (Number)
Composition of households
Hsehld_1_m -- Number of one-person male households. (Number)
Hsehld_1_f -- Number of one-person female households. (Number)
Marhh_chd -- Number of households with a married couple and related children. (Number)
Marhh_no_c -- Number of households with a married couple and no related children. (Number)
Mhh_child -- Number of households with a man and children but no wife. (Number)
Fhh_child -- Number of households with a woman and children but no husband. (Number)
Housing unit information
Hse_units -- Total number of housing units. (Number)
Vacant -- Number of housing units that are vacant. (Number)
Owner_occ -- Number of housing units that are occupied by the owner. (Number)
Renter_occ -- Number of housing units that are occupied by renters. (Number)
Median_val -- Median value of all housing units. (Number)
Medianrent -- Median rent charged for all housing units that are rented. (Number)
Units_1det -- Number of housing units with one detached unit in the structure. (Number)
Units_1att -- Number of housing units with one attached unit in the structure. (Number)
Units2 -- Number of housing units with two units in the structure. (Number)
Units3_9 -- Number of housing units with three to nine units in the structure. (Number)
Units10_49 -- Number of housing units with 10 to 49 units in the structure. (Number)
Units50_up -- Number of housing units with 50 or more units in the structure. (Number)
Mobilehome -- Number of mobile homes or trailers. (Number)
Farm information
Note  Attribute values of -99 in the following fields are null values (data not available).
No_Farms87 -- Total number of farms. (Number)
Avg_size87 -- Average farm size in acres. (Number)
Crop_acr87 -- The total area of cropland in acres. (Number)
Avg_sale87 -- Average sales of agricultural products per farm, in thousands of dollars. (Number)
Counties/Dtl_cnty -- U.S. Counties
3,140 polygons, 52 descriptive fields. Defines U.S. counties.
Fields:
Name -- The county name. (String)
State_name -- The name of the state in which the county is located. (String)
State_fips -- The state FIPS code.  Example:  23 for Maine. (String)
Cnty_fips -- The county FIPS code.  Example:  361 for Orange County, Texas. (String)
Fips -- The combined state and county FIPS code. County FIPS codes begin with 001 for each state, so you must use the combined code to uniquely identify a county in the country. (String)
Area -- The area of the county in square miles based on an Albers Equal Area Projection. (Numeric)
Pop1990 -- The population of the county in 1990 based on the US Census. (Numeric)
Pop1997 -- The population of the county in 1997 estimated by Claritas. (Numeric)
Pop90_sqmi -- The 1990 population per square mile for a county. (Number)
Households -- Total number of households. (Number)
Population by race and ethnicity
Males -- Number of males. (Number)
Females -- Number of females. (Number)
White -- Number of people identified as white. (Number)
Black -- Number of people identified as black. (Number)
Ameri_es -- Number of people identified as American Indian, Eskimo, or Aleut. (Number)
Asian_pi -- Number of people identified as Asian or Pacific Islander. (Number)
Other -- Number of people identified as belonging to a race other than white, black, American Indian, or Asian. (Number)
Hispanic -- Number of people of all races identified as being of Hispanic origin. (Number)
Population by age
Age_under5 -- Number of people 0 to 4 years of age. (Numeric)
Age_5_17 -- Number of people 5 to 17 years of age. (Numeric)
Age_18_29 -- Number of people 18 to 29 years of age. (Numeric)
Age_30_49 -- Number of people 30 to 49 years of age. (Numeric)
Age_50_64 -- Number of people 50 to 64 years of age. (Numeric)
Age_65_up -- Number of people 65 years of age and over. (Numeric)
Population by marital status
Nevermarry -- Number of people who have never been married. (Number)
Married -- Number of people who are married. (Number)
Separated -- Number of people who are separated from their spouse. (Number)
Widowed -- Number of people whose spouse died. (Number)
Divorced -- Number of people who are divorced. (Number)
Composition of households
Hsehld_1_m -- Number of one-person male households. (Number)
Hsehld_1_f -- Number of one-person female households. (Number)
Marhh_chd -- Number of households with a married couple and related children. (Number)
Marhh_no_c -- Number of households with a married couple and no related children. (Number)
Mhh_child -- Number of households with a man and children but no wife. (Number)
Fhh_child -- Number of households with a woman and children but no husband. (Number)
Housing unit information
Hse_units -- Total number of housing units. (Number)
Vacant -- Number of housing units that are vacant. (Number)
Owner_occ -- Number of housing units that are occupied by the owner. (Number)
Renter_occ -- Number of housing units that are occupied by renters. (Number)
Median_val -- Median value of all housing units. (Number)
Medianrent -- Median rent charged for all housing units that are rented. (Number)
Units_1det -- Number of housing units with one detached unit in the structure. (Number)
Units_1att -- Number of housing units with one attached unit in the structure. (Number)
Units2 -- Number of housing units with two units in the structure. (Number)
Units3_9 -- Number of housing units with three to nine units in the structure. (Number)
Units10_49 -- Number of housing units with 10 to 49 units in the structure. (Number)
Units50_up -- Number of housing units with 50 or more units in the structure. (Number)
Mobilehome -- Number of mobile homes or trailers. (Number)
Farm information
Note  Attribute values of -99 in the following fields are null values (data not available).
No_Farms87 -- Total number of farms. (Number)
Avg_size87 -- Average farm size in acres. (Number)
Crop_acr87 -- The total area of cropland in acres. (Number)
Avg_sale87 -- Average sales of agricultural products per farm, in thousands of dollars. (Number)
U.S. States and Counties - Technical Description
GeoDataset names:  States/Dtl_st and Counties/Dtl_cnty
Shapefile names:  States.shp, Dtl_st.shp, Counties.shp and Dtl_cnty.shp
Path: ESRI Data and Maps 1 (CD) \usagen,  ESRI Data and Maps 2 (CD) \usadet,  ESRI Data and Maps 1 (CD) \usagen,  ESRI Data and Maps 2 (CD) \usadet
GeoDataset type: States and Counties are ESRI shapefiles with associated attribute tables. 
GeoDataset lineage: U.S. States and Counties were generalized from ESRI's ArcUSA 1:25,000,000-scale database. The U.S. subregions are as defined by the U.S. Bureau of the Census, except that in this GeoDataset New England is classified as a subregion instead of a region.  Detailed states and counties were created by aggregating Census tract geography to county and then to state areas.  The boundaries are therefore consistent with the boundaries of the Census tracts and have all of the detailed vertices necessary to maintain consistency with the tract level of detail.
Coordinate system: Latitude/longitude in decimal degrees
Coordinate precision: Double.
Useful display scales:
When displaying all 50 states (i.e., with Alaska and Hawaii)
Largest scale:  1:5,000,000
Smallest scale:  1:25,000,000
When displaying the coterminous United States:
Largest scale:  1:5,000,000
Smallest scale:  1:25,000,000
When displaying states:
Largest scale:  1:5,000,000
Smallest scale:  1:30,000,000
When displaying substate areas using the detailed data:
Largest scale:  1:50,000
Smallest scale:  1:500,000
When displaying individual states, the following scales are useful starting points:
Large states:  1:12,000,000
Medium-sized states:  1:5,000,000
Alaska:  Largest scale:  1:8,000,000
Smallest scale:  1:20,000,000
Hawaii:  Largest scale:  1:4,000,000
Smallest scale:  1:15,000,000
When displaying counties:
Largest scale:  1:5,000,000
Smallest scale:  1:20,000,000
Independent city areas (county equivalents) are clearly discernible only at scales of 1:10,000,000 or larger.
Usage notes: FIPS codes for states and counties are not always sequential. Some numbers are skipped to allow for alphabetical additions.