1924- Society for Human Rights formed in Chicago for gay rights.
1951- A gay rights organizations called the Mattachine Society is formed by Harry Hay.
1952- Homosexuality is defined as a mental disorder by the American Psychriatric Association.
1956- The Daughters of Bilitis, a national lesbian organization, is formed.
1962- Illinois decriminalizes homosexual acts between consenting adults in private.
1966- National Transsexual Counseling Unit is formed in San Francisco, becoming the first transgender organization.
1973- The American Psychiatric Association removed homosexuality as being a mental disorder.
1976- Harvey Milk is the first openly gay city commissioner in the United States.
1979- National March on Washington for lesbian and gay rights in Washington, D.C. This was the largest political gathering in support of the LGBT rights.
1982- Wisconsin outlaws discrimination on the basis of sexual orientation.
1984- Berkeley, California, offers its employees domestic partnership benefits.
1993- “Don’t Ask, Don’t Tell” policy is issued by military.
1996- Congress passed the Defense of Marriage Act (DOMA), which defines marriage for all federal law purposes as a legal union between one man and one woman as husband and wife.
2003- Lawrence v. Texas Supreme Court ruling is that state laws banning homosexual sodomy are unconstitutional.
2003- Massachusetts allows same-sex marriage.
2007- House of Representatives approves bill requiring equal rights in the workplace for gays, lesbians, and bisexuals.
2008- Connecticut legalizes same-sex marriage.
2008- California citizens approve Proposition 8, which defines marriage in the state constitution as being between a man and a woman. The California Supreme Court ruled the definition unconstitutional.
2009- Iowa legalizes same-sex marriage
2008-2014- Constant battle in states over gay rights.
2012- Maine, Maryland, and Washington legalize same-sex marriage by popular vote. New Jersey legalizes same-sex marriage.
2013- Supreme Court invalidated the Defense of Marriage Act to the extent that it invalidated same-sex marriages recognized by states.
2015- June 16, the Supreme Court rules same-sex marriage is legal throughout the United States.