The U.S. Census counts every resident in the United States. It is mandated by Article I, Section 2 of the Constitution and takes place every 10 years. The data collected by the decennial census determine the number of seats each state has in the U.S. House of Representatives and is also used to distribute billions in federal funds to local communities.
Resources on the web about poverty typically come from government sources and non-profit organizations.
Most states have an online clearinghouse for demographic data. For example, Iowa has the State Data Center (see link below). Most often the information is from the census data but it is usually presented in an easy-to-follow format.
In a search engine, type the name of any state followed by the words "state data" or "state demographics" (example: Tennessee state data).
The Census Bureau conducts nearly one hundred surveys and censuses every year. By law, no one is permitted to reveal information from these censuses and surveys that could identify any person, household, or business.
Data from the following surveys and censuses are available (or in progress) in American FactFinder: