This section within the Census Bureau's site bring together data sources, publications, links to other source, and much more.
You can find the most recent data in several subject areas, including poverty and income, in the American Factfinder and American Community Survey sections of the site. Another useful area is Well-Being.
This U.S. Department of Health and Human Services site contains data on guidelines and other measures, as well as links to other important research sites. Be sure to look at the "Are You Looking For" section at the bottom of the page.
Section of the U.S. Bureau of Labor Statistics site includes the annual A Profile of the Working Poor, along with data on wages, earning, and benefits, while coordinating other data with the Census Bureau's "Current Population Survey."
The U.S. House Committee on Ways and Means periodically publishes this collection (formally entitled Background Material and Data on Programs Within the Jurisdiction of the Committee on Ways and Means), a unique overview of such program areas as Medicare, social security, unemployment compensation, child care, Temporary Assistance for Needy Families, and more.
U.S. Department of Agriculture research focusing on the "economic, social, and demographic factors that affect the poverty status and incomes of rural residents and their participation in Federal assistance programs."
U.S. Federal Government -- Search Tools
These are tools for finding information from the Congress and Executive agencies of the U.S. Federal Government.
This is almost certainly the most comprehensive database of Congressional publications, some dating back as far as the late 1700's. Includes the complete texts of hearings and most other documents. An interesting sub-set of the database provides legislative histories. (Law Library subscription.)
Probably the single most useful published collection of statistical information on virtually all aspects of life in the United States. And it usually directs you to the originally-published sources of data for more in-depth coverage. Earlier editions also are available online from the Census Bureau. Printed copies (1878-2011) are available in the library's Reference collection.
Contains references to tens of thousands of data sources from the U.S. Federal Government, U.S. state governments, international intergovernmental organizations, and private sector groups, such as trade and professional associations.