Is same-sex marriage legal in the United States?

Answer 1

Yes. Same-sex marriage is legal in all US states and territories effective June 26, 2015, although many states started earlier (shown with the effective dates):

1. Massachusetts (May 17, 2004);
2. Connecticut (October 10, 2008);
3. Iowa (April 27, 2009);
4. Vermont (September 1, 2009);
5. New Hampshire (January 1, 2010);
6. New York (July 24, 2011);
7. Washington (state) (December 6, 2012);
8. Maine (December 29, 2012);
9. Maryland (January 1, 2013);
10. California (June 28, 2013);
11. Delaware (July 1, 2013);
12. Rhode Island (August 1, 2013);
13. Minnesota (August 1, 2013);
14. New Jersey (October 21, 2013);
15. Hawaii (December 2, 2013);
16. New Mexico (December 19, 2013, although some counties started earlier);
17. Oregon (May 19, 2014);
18. Pennsylvania (May 20, 2014);
19. Illinois (June 1, 2014) (although some counties started earlier);
20. Utah - October 6, 2014 and December 20, 2013 to January 6, 2013
21. Wisconsin - October 6, 2014 (and one day on June 6, 2014)
22. Indiana - October 6, 2014
    
23. Virginia - October 6, 2014
24. Oklahoma - October 6, 2014
25. Colorado - October 6, 2014
26. Idaho - October 7, 2014
27. Nevada - October 7, 2014
28. West Virginia - October 9, 2014
29. North Carolina - October 9, 2014
30. Alaska - October 12, 2014
31. Arizona - October 17, 2014
32. Wyoming - October 23, 2014
33. Missouri - (partial) November 5, 2014
34. Kansas - November 13, 2014
35. South Carolina - November 19, 2014
36. Montana - November 19, 2014
37. Florida - January 5, 2015
38. Alabama - January 23, 2015

Washington, DC, legalized same-sex marriage on March 3, 2010.