The Census Bureau reports poverty data from several major household surveys & programs. The Annual Social & Economic Supplement (ASEC) & Current Population Survey (CPS) is the source of official national poverty estimates. The American Community Survey (ACS) provides single & multi-year estimates for smaller areas. The Small Area Income and Poverty Estimates (SAIPE) program provides model-based poverty estimates for counties and school districts.
The Survey of Income & Program Participation (SIPP) provides longitudinal estimates.