Data: Government, State, City, Local and Public

AWS (Amazon Web Services) Public Data Sets, provides a centralized repository of public data sets that can be seamlessly integrated into AWS cloud-based applications.
Datacatalogs.org, open government data from US, EU, Canada, CKAN, and more.
DataMarket, visualize the world's economy, societies, nature, and industries, with 100 million time series from UN, World Bank, Eurostat and other important data providers.
datamob, Public data put to good use.
Enigma, "Google for public data", provides easy access to government, NGO, and other public domain datasets.
Freebase, a community-curated database of well-known people, places, and things.
Google Public Data, with dynamic visualization and exploration tools.
Knoema World Data Atlas, over 1000 indicators on all countries
National Government Statistical Web Sites, data, reports, statistical yearbooks, press releases, and more from about 70 web sites, including countries from Africa, Europe, Asia, and Latin America.
Open Data Census, assesses the state of open data around the world.
Open Data Institute, catalysing the evolution of open data culture to create economic, environmental, and social value.
Socrata OpenData, provides social data discovery services for opening government, healthcare, energy, education, or environment data.
Visualing Data big collection of sites and services for accessing data.

The World Bank, a comprehensive set of data about development in countries around the globe.
UN data, a data access system to UN databases
UNICEF statistics, data analysis and other data about UNICEF work.

Berkeley-curated US statistical information, by UC Berkeley Graduate School of Journalism, providing a wealth of demographic and other data on a city, county, state and national level.
Bitly 1.usa.gov data, anonymized clicks on gov links.
CMS.gov Centers for Medicare and Medicaid Services, Research, Statistics, Data, and Systems.
Data.CMS.gov, Medicare part D prescriber look-up tool.
Data.gov/Education, central guide for education data resources including high-value data sets, data visualization tools, resources for the classroom, applications created from open data and more.
Data USA, a comprehensive visualization of US public data.
DataFerrett, a data mining tool that accesses and manipulates TheDataWeb, a collection of many on-line US Goverment datasets.
EconData, thousands of economic time series, produced by a number of US Government agencies.
FEDSTATS, a comprehensive source of US statistics and more.
FiscalData, your hub for federal financial data.
United States Census Bureau.

CA: San Francisco Data, a clearinghouse of datasets available from the City and County of San Francisco, CA.
IL: Chicago data .
NY: New York NYC Open Dat
Data.Virginia, provides easy access to Virginia open data.
WA: Seattle data .

Europeana Data, contains open metadata on 20 million texts, images, videos and sounds gathered by Europeana - the trusted and comprehensive resource for European cultural heritage content.
Eurostat, the leading provider of high quality statistics on Europe.
OECD Data Lab, data visualisations and European data downloads.
PublicData.eu, access to open, freely reusable datasets from local, regional and national public bodies across Europe.

Data.gov.uk, publicly available data from UK.
London datastore.
UK Office for National Statistics (ONS), UK largest independent producer of official statistics and the recognised national statistical institute of the UK.
UK Data Service, UK largest collection of digital social research data from ESDS, Census Programme, Secure Data Service and others.

Census India, data on population, economic activity, literacy, education, housing, urbanisation, fertility, mortality, and more.
Open Government Data (OGD) Platform, India.

Data.gov.au provides an easy way to find, access and reuse public datasets from the Australian Government.
Australian Bureau of Statistics, access to the full range of ABS statistical and reference information.
Wiki New Zealand, a collaborative website making data about New Zealand accessible for everyone.

Open Data for Africa, supporting statistical development in Africa as a sound basis for designing and managing effective development policies for reducing poverty on the continent.