Open data sets are available to public by the US government and other entities. Here is a list of some open data set providers.
Data.gov
Data.gov managed by the U.S. government provides data, tools, and resources to conduct research, develop web and mobile applications, design data visualizations, and more.
The data available on the following topics.
Census.gov
The U.S. government’s Census Bureau's mission is to serve as the leading source of quality data about the nation's people and economy.
http://www.census.gov/data.html
Open Data Network
The Open Data Network connects publishers of high-value data to the businesses, developers, and analysts that use, reuse, and enrich data. The members of the network work together to share best practices, adopt standards, and advocate for open data broadly.
http://www.opendatanetwork.com/
DataPortals.org
DataPortals.org is the most comprehensive list of open data portals in the world. It is curated by a group of leading open data experts from around the world - including representatives from local, regional and national governments, international organizations such as the World Bank, and numerous NGOs.
HealthData.gov
HealthData.gov website is dedicated to making high value health data more accessible to entrepreneurs, researchers, and policy makers in the hopes of better health outcomes for all.
AWS Public Data Sets
Public Data Sets on AWS provides a centralized repository of public data sets that can be seamlessly integrated into AWS cloud-based applications. AWS is hosting the public data sets at no charge for the community, and like all AWS services, users pay only for the compute and storage they use for their own applications. Learn more about Public Data Sets on AWS and visit the Public Data Sets forum.
http://aws.amazon.com/datasets/
UNICEF
UNICEF has learned through experience that problems that go unmeasured often go unsolved. In collaboration with a wide range of partners, UNICEF gathers evidence on the situation of children and women around the world. It uses this knowledge to inform national and global decision-making with the objective of improving children’s well-being.
