Founded by the Bavarian-born Henry Gerber (1892-1972) in Chicago. The society is the first gay rights organization as well as the oldest documented in America. After receiving a charter from the state of Illinois, the society publishes the first American publication for homosexuals, Friendship and Freedom.

Within a year of its creation, the Society for Human Rights disbanded due to Gerber’s arrest after publication of the Society’s second newsletter.

In 1947, at the beginning of the Cold War, the State Department began campaigns to rid the department of communists and homosexuals, by establishing a set of "security principles" that went on to inspire the creation of a dual loyalty-security test which became the model for other government agencies, as well as the basis for a government-wide security program under the Eisenhower administration.

More than 4,380 gay men and women had been discharged from the military and around 500 fired from their jobs with the government.

Published by biologist and sex researcher Alfred Kinsey (1894-1956), the report concludes that homosexual behavior is not restricted to people who identify themselves as homosexual and that 37% of men have enjoyed homosexual activities at least once.

While psychologists and psychiatrists in the 1940s consider homosexuality a form of illness, the findings surprise many conservative notions about sexuality.

Christine Jorgensen (1926-1989) makes international headlines as the first person in the U.S. to undergo a successful gender-reassignment operation.

She became an instant celebrity, known for her directness and polished wit, and used the platform to advocate for transgender people.

In Los Angeles, gay rights activist Harry Hay (1912-2002) founds America’s first sustained national gay rights organization: The Mattachine Society.

The society aimed to "eliminate discrimination", assimilate homosexuals into mainstream society, and cultivate an "ethical homosexual culture."

A Senate report titled "Employment of Homosexuals and Other Sex Perverts in Government" is distributed to members of Congress.

The report states homosexuals have a mental illness, and "constitute security risks" to the nation.

The American Psychiatric Association lists homosexuality as a sociopathic personality disturbance in its first publication of the Diagnostic and Statistical Manual of Mental Disorders.

The findings are criticized due to lack of empirical and scientific data.

President Eisenhower signs Executive Order 10450, banning homosexuals from working for the federal government or any of its private contractors.

The Order lists homosexuals as security risks, along with alcoholics and neurotics.

In San Francisco, Phyllis Lyon and Del Martin co-found The Daughters of Bilitis, the first organization for lesbians in the United States.

The organization hosts social functions, providing alternatives to lesbian bars and clubs, which were frequently raided by police.

The Ladder was the first nationally distributed lesbian publication in the United States from 1956 to 1972. It was the primary publication and method of communication for the Daughters of Bilitis, supported by ONE, Inc. and the Mattachine Society.

The name of the magazine was derived from the artwork on its first cover, simple line drawings showing figures moving towards a ladder that disappeared into the clouds.

One, Inc. v. Olesen, was a landmark decision of the US Supreme Court for LGBT rights in the United States. It was the first U.S. Supreme Court ruling to deal with homosexuality and the first to address free speech rights with respect to homosexuality. The Supreme Court reversed a lower court ruling that the gay magazine ONE (a spinoff of The Mattachine Society) violated obscenity laws, thus upholding constitutional protection for pro-homosexual writing.

Illinois repeals its sodomy laws, becoming the first U.S. state to decriminalize homosexuality.

At Independence Hall in Philadelphia, picketers begin staging the first Reminder Day to call public attention to the lack of civil rights for LGBT people. The gatherings will continue annually for five years.

Members of The Mattachine Society stage a "sip-in" at the Julius Bar in Greenwich Village, where the New York Liquor Authority prohibits serving gay patrons in bars on the basis that homosexuals are "disorderly."

Following the sip-in, The Mattachine Society sues the New York Liquor Authority. Although no laws are overturned, the New York City Commission on Human Rights declares that homosexuals have the right to be served.

After transgender customers become raucous in a 24-hour San Francisco cafeteria, management calls police. When an officer manhandles one of the patrons, she throws coffee in his face and a riot ensues.

Following the riot, activists established the National Transsexual Counseling Unit, the first peer-run support and advocacy organization in the world.

Patrons of the Stonewall Inn in NYC's Greenwich Village riot when police officers attempt to raid the popular gay bar around 1am. While police raids on gay bars were routine in the 1960s, officers quickly lost control of the situation. Tensions between New York City Police and gay residents of Greenwich Village erupted into more protests the next evening and again several nights later.

The three-day riot included thousands of protestors but received only minimal news coverage.

Christopher St. Liberation Day commemorates the one-year anniversary of the Stonewall riots. Following the event, thousands of members of the LGBT community march through New York into Central Park, in what will be considered America's first gay pride parade.

The board of the American Psychiatric Association votes to remove homosexuality from its list of mental illnesses.

Singer and conservative Southern Baptist Anita Bryant leads a successful campaign with the "Save Our Children" Crusade to repeal a gay rights ordinance in Dade County, Florida. Bryant faces severe backlash from gay rights supporters across the U.S.

Harvey Bernard Milk (1930-1978) was the first openly gay man to be elected to public office in California, as a member of the San Francisco Board of Supervisors in 1977. A year later, on November 27, 1978, former city supervisor Dan White assassinates Milk. White's actions are motivated by jealousy and depression, rather than homophobia.

Former San Francisco city supervisor Dan White is convicted of voluntary manslaughter and is sentenced to seven years in prison for the assassination of Harvey Milk and George Moscone. More than 5,000 outraged protesters ransack San Francisco's City Hall.

The following night, approximately 10,000 people gather on San Francisco's Castro and Market streets for a peaceful demonstration to commemorate Milk's 49th birthday.

An estimated 75,000 people participate in the National March on Washington for Lesbian and Gay Rights - demanding equal civil rights and urge for the passage of protective civil rights legislature.

AIDS, Acquired Immunodeficiency Syndrome, was identified by the U.S. Centers for Disease Control and Prevention (CDC). Its cause—HIV, Human Immunodeficiency Virus—was identified in the earlier part of the decade.

AIDS was first clinically reported on June 5, 1981, with five cases in the United States. The initial cases were a cluster of injecting drug users and gay men with no known cause of impaired immunity.

The New York Times prints the first story of a rare pneumonia and skin cancer found in 41 gay men in New York and California. The CDC initially refers to the disease as GRID, Gay Related Immune Deficiency Disorder.

When the symptoms are found outside the gay community, Bruce Voeller, biologist and founder of the National Gay Task Force, successfully lobbies to change the name of the disease to AIDS.

AIDS advocacy group ACT UP (The AIDS Coalition to Unleash Power) is formed in response to the devastating affects the disease has had on the gay and lesbian community in New York.

The group holds demonstrations against pharmaceutical companies profiteering from AIDS-related drugs as well as the lack of AIDS policies protecting patients from outrageous prescription prices.

Hundreds of thousands of activists take part in the National March on Washington to demand that President Reagan address the AIDS crisis.

It is not until the end of his presidency that Reagan speaks publicly about the epidemic.

The CDC mails a brochure, Understanding AIDS, to every household in the U.S. Approximately 107 million brochures are mailed.

President George Bush signs the Ryan White Care Act, a federally funded program for people living with AIDS.

Ryan White (1971-1990), an Indiana teenager, contracted AIDS in 1984 through a tainted hemophilia treatment. After being barred from attending school because of his HIV-positive status, White becomes a well-known activist for AIDS research and anti-discrimination.

Created by the New York-based Visual AIDS, the red ribbon is adopted as a symbol of awareness and compassion for those living with HIV/AIDS.

The Department of Defense issues a directive prohibiting the U.S. Military from barring applicants from service based on their sexual orientation. "Applicants shall not be asked or required to reveal whether they are homosexual, " states the new policy, which still forbids applicants from engaging in homosexual acts or making a statement that he or she is homosexual. This policy is known as "Don't Ask, Don't Tell."

In the case of Romer v. Evans, the United States Supreme Court decides that Colorado's 2nd amendment, denying gays and lesbians protections against discrimination, is unconstitutional, calling them "special rights."

President Clinton signs the Defense of Marriage Act into law. The law defines marriage as a legal union between one man and one woman and that no state is required to recognize a same-sex marriage from out of state.

On the night of October 6, 1998, Matthew Shepard (1976-1998) was offered a ride home by two men at the Fireside Lounge in Laramie, WI. The men drove to a remote rural area and proceeded to rob, pistol-whip, and torture Shepard, tying him to a barbed-wire fence and leaving him to die. Still tied to the fence, Shepard remained in a coma for eighteen hours when he was discovered by a cyclist who mistook him for a scarecrow.

Shepard was pronounced dead six days after the attack.

Vermont becomes the first state in the U.S. to legalize civil unions and registered partnerships between same-sex couples.