The data set includes a wide range of economic, social and geographic information for every U.S. congressional district, from 1943-1998..

A repository of detailed election results at the constituency level for lower house legislative elections from around the world.

The first truly large-scale academic survey project aimed at studying the midterm Congressional elections..

Daily Kos Elections guide to all of their datasets..

Provides free access to a rich dataset of constituency election results in 110 countries and territories throughout the world..

International election data, reports on electoral systems around the world..

The ELECLAW indicators measure the degree of inclusion of the electoral franchise for three categories of potential voters or candidates: resident citizens, non-resident citizens and non-citizen residents..

Interactive Shiny app shows world map and frequencies of electoral system by decade..

Some of these files are very large and challenging to work with, but the FEC makes a lot of data available.

Information on the results of both national and subnational elections around the world..

Multiple key indicatiors of voter participation at state level since 1960s and 1970s..

Helpful site from Missouri for advanced analysis of Census data.

Supports advances in election science by collecting, analyzing, and sharing core data and findings..

Detailed information on all election events from 1945-2012..

Data on student registration and voting rates, and an examination of campus climate for political learning and engagement..

To help everyone understand the ads they see online, this report from Google includes information about verified advertisers, spending on ads related to elections..

Resource designed to be used by voters, community groups, activists, and lawyers to help fully enfranchise voters of color in local government..

an information source for the United States electoral system..

From the Office of the Clerk, official vote counts in congressional elections since 1920.

From the International Institute for Democracy and Electoral Assistance (IDEA).

seeks to develop better voting technologies, to improve election administration, and to deepen scientific research in these areas.

Tracks and analyzes all broadcast advertisements aired by or on behalf of federal and state election candidates in every media market in the country, data access..