Data.gov provides descriptions of the Federal datasets (metadata), information about how to access the datasets, and tools that leverage government datasets.
This HHS site is dedicated to making high value health data more accessible to entrepreneurs, researchers, and policy makers. Search for high-quality data by topic.
Categorized into 21 market sectors, Statista provides access to quantitative data on media, business, finance, politics, and a wide variety of other areas of interest or markets.
The ProQuest Statistical Abstract of the United States is the authoritative and comprehensive summary of statistics on the social, political, and economic conditions of the United States. The data is the most current from the Census Bureau and is updated online.