The Society for Human Rights in Chicago became the country's earliest known gay rights organization.
The New York Times becomes the first major publication to use the word "homosexuality."
Alfred Kinsey publishes Sexual Behavior in the Human Male, revealing to the public that homosexuality is far more widespread than was commonly believed.
The Mattachine Society, the first national gay rights organization, is formed by Harry Hay in Los Angeles, considered by many to be the founder of the gay rights movement.
Illinois becomes the first state in the U.S. to decriminalize homosexual acts between consenting adults in private.
Riots follow a police raid on the gay bar Stonewall Inn, in Greenwich Village, New York. It is seen as the start of the gay rights movement in the U.S and around the world.
Jack Baker and James Michael McConnell apply for a marriage license in Hennipen County, Minnesota.
The American Psychiatric Association removes homosexuality from its official list of mental disorders.
About 75,000 people participated in the National March on Washington for Lesbian and Gay Rights in Washington, D.C., in October.
At the 1980 Democratic National Convention held at New York City's Madison Square Garden, Democrats took a stance supporting gay rights.
First domestic partnership laws are passed.
Denmark was the first in the world to enact registered partnership laws for same-sex couples, allowing most of the same rights as marriage.
If elected, Bill Clinton promised to reverse the executive order banning gays and lesbians from serving in the U.S. military.
Vermont becomes the first state in the country to legally recognize civil unions between gay or lesbian couples.
On February 14, same-sex couples from Marriage Equality USA began asking for marriage licenses in Los Angeles, New York City and San Francisco.
The Massachusetts Supreme Judicial Court ruled that banning gays and lesbians from marrying violates the state constitution.
The newly-elected San Francisco mayor Gavin Newsom issues the first same-sex marriage certificates in the U.S.
On May 17, same-sex marriage becomes legal in Massachusetts.
California and Connecticut's Supreme Court legalizes same-sex marriage.
Twelve states and the District of Columbia have legalized gay marriage at this point.
12 out of 194 countries allow same-sex marriage.