Same-sex marriage in the United States
Also available on the Windows Store, on the Windows Phone Marketplace: 
, and on the HP TouchPad: 
Here's another nice visualization based on this data - check it out!
FAQ:
- What is this? This is an interactive map showing the legality of same-sex (gay) marriage and civil unions in the United States.
- How can I find more information about a state? Click on the state to get a timeline of important events regarding same-sex marriage law.
- What's a cartogram? A cartogram is a kind of map that shows states roughly in proportion to their population, and so it's more representative of how many people in the US are living under which laws. In this case, I based the cartogram on this Wikipedia cartogram of the 2008 election. Ideally the cartogram would change based on what year we're showing to keep up with population. Also note that small states are slightly overrepresented since every state gets at least 3 electoral votes.
- What's the deal with Colorado? In the past, some states like Colorado and Nevada had civil unions, but marriage was against the constitution. I went with the green color instead of the dark red to emphasize that same-sex couples did have some rights, which seems more important than the fact that marriage was off limits.
- How did you determine the difference between "Civil unions" and "Civil unions with some rights included in marriage"? I mostly relied on the determination made by the Human Rights Campaign - here's a PDF map of the states that currently recognize same-sex marriage and civil unions.
- Where can I find more information about interstate relationship recognition, hospital visitation laws, etc.? The Human Rights Campaign maintains a number of maps covering these issues. Another good resource is Lambda Legal's map of pending marriage equality cases.
- How does the map work? The map uses a React package I made called usStateMap, which uses SVG. You can also see a previous version of this page that used an HTML Canvas.
- How did you find this data? I did a lot of online research - mostly starting with the Wikipedia page, the Marriage Law Project at The Catholic University of America, and alliancealert.org (formerly domawatch.org).
- Are the source files available? Yes - the same-sex marriage data is available in marriagedata.js, and the rest of the source is on GitHub. You can also see a previous version of this page that doesn't use React (like this one does).
- How can I contact you? Just email me at greg@gregstoll.com.
Map colors based on www.ColorBrewer.org, by Cynthia A. Brewer, Penn State.