Data.gov
data.gov
The official open data portal of the US federal government, providing access to hundreds of thousands of datasets from government agencies.
Why it is useful
The primary source for authoritative US government datasets across every domain — from FDA drug approvals to NOAA weather readings. Quality and format consistency varies by agency, but for anything where an official government dataset exists, this is the right starting point. The catalog is searchable by topic, format, and publishing agency.