January 14 – The Green Bay Packers win Super Bowl II.

January 21 – A U.S. B-52 Stratofortress crashes in Greenland, discharging 4 nuclear bombs.

January 22 – Rowan & Martin's Laugh-In debuts on NBC.

January 23 – North Korea seizes the USS Pueblo, claiming the ship violated its territorial waters while spying.

January 30 – The Viet Cong and North Vietnam launch the Tet Offensive against South Vietnam, the United States, and their allies.

January 31 – Viet Cong soldiers attack the US Embassy, Saigon.

February 1 - Vietnam War: A Viet Cong officer named Nguyễn Văn Lém is executed by Nguyễn Ngọc Loan, a South Vietnamese National Police Chief. The event is photographed by Eddie Adams. The photo makes headlines around the world, eventually winning the 1969 Pulitzer Prize, and sways U.S. public opinion against the war.

February 11 – Madison Square Garden in New York City opens

March 16 – Vietnam War – My Lai massacre: American troops kill scores of civilians. The story will first become public in November 1969 and will help undermine public support for the U.S. efforts in Vietnam.

March 16 – U.S. Senator Robert F. Kennedy enters the race for the Democratic Party presidential nomination.

March 31 – U.S. President Lyndon B. Johnson announces he will not seek re-election.

April 4 –Martin Luther King, Jr. is shot dead at the Lorraine Motel in Memphis, Tennessee. Riots erupt in major American cities, lasting for several days afterwards.

April 11 – U.S. President Lyndon B. Johnson signs the Civil Rights Act of 1968.

May 22 – The U.S. nuclear-powered submarine Scorpion sinks with 99 men aboard, 400 miles southwest of the Azores.

June 5 – U.S. presidential candidate Robert F. Kennedy is shot at the Ambassador Hotel in Los Angeles, California by Sirhan Sirhan. Kennedy dies from his injuries the next day

July 1 – The Central Intelligence Agency's Phoenix Program is officially established

July 18 – The semiconductor company Intel is founded.

August 5–8 – The Republican National Convention in Miami Beach, Florida nominates Richard Nixon for U.S. President and Spiro Agnew for Vice President.

September 7 – 150 women (members of New York Radical Women) arrive in Atlantic City, New Jersey to protest against the Miss America Pageant, as exploitative of women. Led by activist and author Robin Morgan, it is one of the first large demonstrations of Second Wave Feminism as Women's Liberation begins to gather much media attention.

September 24 – 60 Minutes debuts on CBS

October 8 – Vietnam War – Operation Sealords: United States and South Vietnamese forces launch a new operation in the Mekong Delta.

October 11 – Apollo program: NASA launches Apollo 7, the first manned Apollo mission (Wally Schirra, Donn Eisele, Walter Cunningham). Mission goals include the first live television broadcast from orbit and testing the lunar module docking maneuver.

October 14 – Vietnam War: The United States Department of Defense announces that the United States Army and United States Marines will send about 24,000 troops back to Vietnam for involuntary second tours.

October 16 – In Mexico City, Tommie Smith and John Carlos, 2 black Americans competing in the Olympic 200-meter run, raise their arms in a black power salute after winning, respectively, the gold and bronze medals for 1st and 3rd place

October 25 – The Jimi Hendrix Experience releases Electric Ladyland.

October 31 – Vietnam War: Citing progress in the Paris peace talks, U.S. President Lyndon B. Johnson announces to the nation that he has ordered a complete cessation of "all air, naval, and artillery bombardment of North Vietnam" effective November 1

November 2 - U.S. presidential election, 1968: Republican challenger Richard M. Nixon defeats the Democratic candidate, Vice President Hubert Humphrey, and American Independent Party candidate George C. Wallace.

November 11 – Vietnam War: Operation Commando Hunt is initiated to interdict men and supplies on the Ho Chi Minh Trail, through Laos into South Vietnam. By the end of the operation, 3 million tons of bombs are dropped on Laos, slowing but not seriously disrupting trail operations.

December 23 – Release of the USS Pueblo crew after spending 11 months in captivity by the North Koreans

December 24 – Apollo Program: U.S. spacecraft Apollo 8 enters orbit around the Moon. Astronauts Frank Borman, Jim Lovell and William A. Anders become the first humans to see the far side of the Moon and planet Earth as a whole

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Undated

In or about this year the HIV virus is thought to have first arrived in the U.S

Ongoing

• Cold War (1945–1991)

• Space Race (1957–1975)

• Vietnam War, U.S. involvement (1962–1973)

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