The U.S. Constitution requires the federal government conduct the Decennial (i.e., every 10 years) Census for the purpose of Congressional reapportionment. The most recent Decennial Census was taken in 2010, and the first Census was taken in 1790.
The original and primary purpose of the Census is to provide an accurate population count to determine how seats in the U.S. House of Representatives are apportioned. Census data is now used to draw congressional and state legislative district boundaries, to allocate federal and state funds, to formulate public policy, and to assist with planning and decision making in the private sector.
The Census questions have changed throuout the years; in 1790 only the heads of household (as defined at that time) were counted, since they were the only persons allowed to vote. The Census now attempts to count every person in the United States, with efforts made to count undocumented residents ("illegal immigrants"), homeless persons, persons residing in nursing homes, and more. Portions of the population slip through and remain uncounted, so this is not a 100% count but is the most accurate data collected on population for the nation, states, counties, cities, and neighborhoods.
Area neighborhoods such as Milwaukee's River West or Brady Street areas are not searchable through the Census by the local name. Your best option for locating data files relevant to your community area is to start with an address search for a school, church, or establishment in that neighborhood.
For example, enter the UWM Libraries street address (2311 E Hartford Avenue, Milwaukee, WI 53211) to determine the Census location:
Wisconsin; Milwaukee County; Milwaukee City; Census Tract 74; Blook Group 1; Block 1007
See the UWM Libraries Milwaukee Neighborhoods Guide for other options based on the 2000 Census.
American FactFinder (AFF) contains data from the decennial censuses conducted in 2010 and 2000. Selected data from 1990 and prior censuses may be found through the Census Bureau's home page search or from the Census 2000 Gateway. Data from prior Census years is scattered, with some data files and print tables available.
Why the Census Matters is a Wisconsin Public Radio podcast (06/16/2015) from the Kathleen Dunn Show. Guest Phil Sparks, co-founder of the advocacy organization The Census Project provides a good introduction to the historic Census "long form", household sampling, and how it evolved into the current American Community Survey. Visit the What is the American Community Survey? Census site for official information guides, and more.
Census Data and Tables will indicate the source, using an abbreviated code of SF# or STF#. What is covered?
SF = Summary File; STF = Summary Tape File
Summary File 1 (SF 1) - referred to as the 100% data or "short form". Contains data on age, sex, households, families, and housing units based on answers to the questions common to both the (2000 and earlier) Census "Short-Form" and "Long-Form" questionnaires. Detailed searchable fields include Age, Hispanic or Latino Origin, Household Relationship, Owners and Renters, Race, Sex, and more...
Summary File 2 (SF2) - referred to as "subject files", among others. Tables for detailed population groups, including American Indian and Alaska Native tribes, and Hispanic or Latino groups. Tables focus on age, sex, households, families, and occupied housing units for the total population of that group. Limitations:
* no tables are available for geographic areas having a population of less than 100
* tables are repeated only for the race groups, American Indian and Alaska Native tribes, and Hispanic or Latino groups having a population of 100 or more within the geographic area.
Summary File 3 (SF 3) - referred to as the Sample Data or "long form". Detailed tables for social, economic and housing characteristics compiled from a sample of approximately 1 in 6 households that received the Census 2000 (or earlier) long-form questionnaire. 50+ tables are repeated for nine major race and Hispanic or Latino groups: White alone; Black or African American alone; American Indian and Alaska Native alone; Asian alone; Native Hawaiian and Other Pacific Islander alone; Some other race alone; Two or more races; Hispanic or Latino; and White alone, not Hispanic or Latino.
Data on Ancestry, Citizenship, Disability, Educational Attainment, Income, Industry, Language Spoken at Home, Marital Status, Migration, Occupation, Place of Birth, Place of Work, Poverty, Rent, School Enrollment, Tenure, Units in Structure, and more...
Summary File 4 (ST 4) - contains tabulations of population and housing data collected from a sample of the population. The data are shown down to the census tract level by detailed race. The 2000 Census includes 336 race, Hispanic or Latino, American Indian and Alaska Native, and ancestry categories for ST 4.