Here are a list of popular statistical resources providing free datasets:

  • Data.Gov
    This US Governmental site aims to improve public access to high value, machine readable datasets generated by the Executive Branch of the Federal Government. Here, you can find data, tools, and resources to conduct research, develop web and mobile applications, design data visualizations, and more.
  • Data-Planet
    Provides access to statistical data produced by U.S. Federal agencies, States, private organizations, and major intergovernmental organizations. There are up to 2 billion charts, maps, views, rankings, time series and tables available for use in the Data-Planet repository. Link to Ready Reference interface.

  •  General Social Survey
    The GSS contains a standard ‘core’ of demographic, behavioral, and attitudinal questions, plus topics of special interest. Many of the core questions have remained unchanged since 1972 to facilitate time-trend studies as well as replication of earlier findings. The GSS takes the pulse of America, and is a unique and valuable resource. It has tracked the opinions of Americans over the last four decades.

  • Integrated Public Use Microdata Series (IPUMS)
    Consists of more than fifty high-precision samples of the American population drawn from fifteen federal censuses and from the American Community Surveys of 2000-2011.

  • The Inter-University Consortium for Political and Social Research (ICPSR)
    The Inter-University Consortium for Political and Social Research. World’s largest archive of social science data. Election data, opinion polls, more. Special collections on Health, Education, Aging, Crime, Substance Abuse. A great place to begin looking for raw data. Many dataset files come formatted for major statistical packages (Stata, SPSS, SAS).

  • iPoll Databank
    Includes all survey data for which the Roper Center holds the datasets as well as survey data from Pew Resarch Centers, Kaiser Family Foundation, Gallup Organization and more.

  • IQSS Dataverse
    Data repository hosted by Harvard University containing raw data files of interdisciplinary research studies in both the sciences and social sciences

  • OECD iLibrary
    OECD iLibrary provides online access to Organisation for Economic Co-operation and Development (OECD) resources, covering trade, environment, agriculture, technololgy, economic development, and more. The books, reports, working papers and periodicals are full-text and the databases have extensive statistical information.

  • Policy Map
    Mapping tool much like Social Explorer but integrates other data sources from the Department of Homeland security, Bureau of Labor Statistics and the U.S Census

  • ProQuest Statistical Insight
    Provides access to statistics and tables in reports produced by federal agencies, states, intergovernmental organizations as well as private enterprise.

  • re3data.org
    Searchable catalog of research data repositories

  • Roper Center
    The Roper Center for Public Opinion Research is one of the world’s leading archives of social science data, specializing in data from surveys of public opinion. Includes over 18,000 datasets across many subjects.

  • Social Explorer
    Interactive visualization tool that utilizes the decennial censuses and American Community Survey data. Also includes select data sets on crime, religion, recent presidential approval ratings and more. Can be used to visually study demography and change over time in the United States.

  • UNdata
    Official statistics produced by countries and compiled by United Nations data system, as well as estimates and projections. The domains covered are agriculture, education, energy, industry, labour, national accounts, population and tourism. Largest aggregator of international data. If you’re looking for data from different countries this is a good place to start.

  • Countrydata.com (PRS Group)