A Census Block Group is a geographical unit used by the United States Census Bureau which is between the Census Tract and the Census Block. It is the smallest geographical unit for which the bureau publishes sample data, i.e. data which is only collected from a fraction of all households. Typically, Block Groups have a population of 600 to 3,000 people.
Every Census Block Group has a unique 12-digit FIPS code. The Block Group's unique identifier is the 12th digit of the FIPS Code. This number determines the first digit of all the census blocks contained within a block group. For instance, census Block Group 2 includes any block numbered 2000 to 2999.
For the 2000 US Census, the United States including Puerto Rico had 211,267 block groups, each containing an average of 39 blocks.
For the 2010 US Census, the United States (not including Puerto Rico, United States Virgin Islands, etc.) had 217,740 block groups, each containing an average of 51 blocks. [1]
The Federal Information Processing Standards (FIPS) of the United States are a set of publicly announced standards that the National Institute of Standards and Technology (NIST) has developed for use in computer systems of non-military, American government agencies and contractors. FIPS standards establish requirements for ensuring computer security and interoperability, and are intended for cases in which suitable industry standards do not already exist. Many FIPS specifications are modified versions of standards the technical communities use, such as the American National Standards Institute (ANSI), the Institute of Electrical and Electronics Engineers (IEEE), and the International Organization for Standardization (ISO).
FIPS state codes were numeric and two-letter alphabetic codes defined in U.S. Federal Information Processing Standard Publication 5-2 to identify U.S. states and certain other associated areas. The standard superseded FIPS PUB 5-1 on May 28, 1987, and was superseded on September 2, 2008, by ANSI standard INCITS 38:2009.
The Federal Information Processing Standard Publication 6-4 is a five-digit Federal Information Processing Standards code which uniquely identified counties and county equivalents in the United States, certain U.S. possessions, and certain freely associated states.
In the United States, a county is an administrative or political subdivision of a state that consists of a geographic region with specific boundaries and usually some level of governmental authority. The term "county" is used in 48 states, while Louisiana and Alaska have functionally equivalent subdivisions called parishes and boroughs, respectively. The specific governmental powers of counties vary widely between the states, with many providing some level of services to civil townships, municipalities, and unincorporated areas. Certain municipalities are in multiple counties; New York City is uniquely partitioned into five counties, referred to at the city government level as boroughs. Some municipalities have consolidated with their county government to form consolidated city-counties, or have been legally separated from counties altogether to form independent cities. Conversely, those counties in Connecticut, Rhode Island, eight of Massachusetts's 14 counties, and Alaska's Unorganized Borough have no government power, existing only as geographic distinctions.
A census tract, census area, census district or meshblock is a geographic region defined for the purpose of taking a census. Sometimes these coincide with the limits of cities, towns or other administrative areas and several tracts commonly exist within a county. In unincorporated areas of the United States these are often arbitrary, except for coinciding with political lines.
In 45 of the 50 states of the United States, the county is used for the level of local government immediately below the state itself. Louisiana uses parishes, and Alaska uses boroughs. In Connecticut, Massachusetts, and Rhode Island, some or all counties within states have no governments of their own; the counties continue to exist as legal entities, however, and are used by states for some administrative functions and by the United States Census bureau for statistical analysis. There are 3,242 counties and county equivalent administrative units in total, including the District of Columbia and 100 county-equivalents in the U.S. territories.
The American Community Survey (ACS) is a demographics survey program conducted by the U.S. Census Bureau. It regularly gathers information previously contained only in the long form of the decennial census, such as ancestry, citizenship, educational attainment, income, language proficiency, migration, disability, employment, and housing characteristics. These data are used by many public-sector, private-sector, and not-for-profit stakeholders to allocate funding, track shifting demographics, plan for emergencies, and learn about local communities. Sent to approximately 295,000 addresses monthly, it is the largest household survey that the Census Bureau administers.
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.
A census block is the smallest geographic unit used by the United States Census Bureau for tabulation of 100-percent data. The number of blocks in the United States, including Puerto Rico, for the 2010 Census was 11,155,486.