Timeline:

Year Month Important Event
Background
111 BC:   China took over North Vietnam.
939 AD:   Vietnam defeated China and ends Chinese rule. Vietnam is influenced by Chinese in almost every aspect.
16th Century:   Imperialistic Europeans begin to colonize Asia.
1847:   French bombard Da Nang due to anti-Catholic campaigns started by the Vietnamese Government.
1857:   French assault on Da Nang marked the beginning of the French military in Indochina.
1883:   French establish the Indochina Union composed of Cochin China (Southernmost tip of Vietnam and Cambodia), Annam (Southern Vietnam), Tonkin (North Vietnam), Cambodia, and Laos.
1890:   Ho Chi Minh was born.
1906:   Phan Boi Chau founds the modernization society by using western ideas, but keeps the patriotism of the Vietnamese.
1919:   Ho Chi Minh taken on the alias of Nguyen Ai Quoc, petitions in the Paris conference for recognition of Vietnam self-determination.
1920:   Ho Chi Minh founds and joins the French Communist Party.
1925:   Bao Dai becomes emperor of Vietnam.
    Phan Boi Chau was put on trial in Hanoi and is sentenced for life due to patriotism.
1927:   Vietnam Nationalist Party (VNQDD) was established.
1930:   Ho Chi Minh founds the Indochinese Communist Party (ICP).
1940:   Japanese takes over the northern part of Indochina during World War II.
1941:   Japanese forces takes over all of Indochina.
    Ho Chi Minh organizes the Vietminh.
1942: General Vo Nguyen Giap organizes the Vietminh guerrilla groups for anti-Japanese activity in North Vietnam.
First Indochina War
1945: August: Japanese surrenders.
    Vietnam proclaim independence as the result of the August Revolution.
  September: British and the Chinese forces occupies Vietnam for the return of French authority.
1946: March: Ho-Sainteny (March) Agreement provides French recognition of Vietnam as a free state within the French Union, with the placement of French troops in North Vietnam.
  June: French violates the March Agreement.
  September: Ho Chi Minh renegotiates the March Agreement in Paris; agrees to put an end to the French-Vietnamese Clash.
  November: Shooting between the French and Vietnamese at Haiphong results in the French naval bombardment.
    Vietminh forces attack the French garrison in Hanoi; marks the beginning of the First Indochina War.
1949:   Elysée Agreement makes Vietnam an "associated state" within the French Union and provides Bao Dai as the emperor.
1950: January: People's Republic of China and USSR recognize the Democratic Republic of Vietnam (DRV).
  February: US recognized the government headed by Bao Dai.
  May: US begin military assistance to the French military in Indochina.
  Sept-Oct: French suffer severe defeats in Northern Vietnam.
1951: Jan-March: French halt Vietminh advance in North Vietnam.
1953:   General Navarre becomes commander of the French forces; plans to win war.
  November: French forces occupy Dien Bien Phu to forestall the Vietminh assault to Laos and establish a base for an offensive against the Vietminh.
1954:   Pham Van Dong named Prime Minister of North Vietnam.
  March: Battle of Dien Bien Phu begins.
    President Eisenhower sets forth the "Domino Theory" and considers interfering in Vietnam.
    French defeated at Dien Bien Phu.
    Indochina phase of the Geneva Conference begins.
  June: Ngo Dinh Diem (backed by US) was named the prime minister of the State of Vietnam (RVN).
  July: Geneva Accords divides Vietnam at the 17th Parallel and states the final declaration of Vietnam depends on a nationwide election in 1956.
Vietnam War
1955: January: US begins direct assistance to the South Vietnam Government; tries to stop the Communist north from taking over the rest of Vietnam.
  February: US advisers replaces the French in training the South Vietnamese troops.
    Diem refuses negotiations with North Vietnam on reunification.
  October: Diem defeats Bao Dai and proclaims himself as president of the Republic of Vietnam (RVN).
1956: July: Election stated in the Geneva Accords are not held.
  December: North Vietnam prepares for "self-defense."
1957: May: Diem visits US to address Congress and reassure Eisenhower's support.
1959: May: North Vietnamese supports Communists in the South by providing weapons and equipments.

Ho Chi Minh Trail is constructed.

1960: December: National Liberation Front (NLF) is established.
1960   US MILITARY FORCES IN VIETNAM- 900
1961:   Robert McNamara becomes US secretary of defense.
  May: Vice-President Lyndon Johnson visits South Vietnam; urges more US aid.
1961   US MILITARY FORCES IN VIETNAM- 3200
1962:   Duong Van Minh becomes military adviser to Diem.

US uses Agent Orange for the first time during the Vietnam War.

1962: February: US Military Assistance Command, Vietnam (MACV) is established.
1962   US MILITARY FORCES IN VIETNAM- 12000
1963:   US begins its development of the Cluster Bomb.
  May: South Vietnamese Police kills 9 Buddhist protesters.
  June: Buddhist Monk, Thich Quang Duc, protests by committing suicide through self-immolation.
  August: South Vietnamese Army (PAVN) attacks Buddhist temple.
  November: Duong Van Minh, Nguyen Van Thieu, Nguyen Cao Ky, and other generals overthrow Diem.

Diem and his brother were murdered.

Kennedy is assassinated.

Vice-President Lyndon Johnson becomes president.

1963   US MILITARY FORCES IN VIETNAM- 16000
1964:   Lyndon Johnson is nominated as president.

General Westmoreland becomes chief of the MACV.

  January: General Nguyen Thieu seizes power in Saigon; exiles Duong Van Minh.
  July: South Vietnamese naval forces carry out raids in North Vietnamese coast.
  August: Crisis arises at Tonkin Gulf; results in the approval of the Tonkin Gulf Resolution.

US retaliates by bombing North Vietnam through air.

  November: Lyndon Johnson wins the US presidential election.
1964   US MILITARY FORCES IN VIETNAM- 23200
1965: February: Viet Cong forces attack US base at Pleiku.

Lyndon Johnson orders retaliatory air attacks against North Vietnam.

First US combat troops arrive.

  March: Lyndon Johnson offers a participation in economic development program if Vietnamese agree to end the war.  Rejected by Communist leaders.

Lyndon Johnson orders a ground combat of 40 thousand troops.

First Teach-In protest at University of Michigan.

  June: Air Marshall Nguyen Cao Ky becomes the prime minister of South Vietnam.
  December: US pauses the air bombing for negotiations.
1965   US MILITARY FORCES IN VIETNAM- 200000
1966: February: Lyndon Johnson meets with South Vietnamese leader in Honolulu.
  March: Buddhists lead massive demonstration to restore civilian headed South Vietnamese Government.
1966   US MILITARY FORCES IN VIETNAM- 400000
1967:   Nguyen Van Thieu defeats Nguyen Cao Ky and becomes president of South Vietnam.
  January: US stops air bombing for peace negotiations.
  February: Operation Junction City attack Communist base near Cambodian border.
  June: Pentagon Papers is commissioned by Secretary of Defense Robert S. McNamara.
  September: Nguyen Van Thieu replaces Nguyen Cao Ky as the prime minister of South Vietnam.  

Lyndon Johnson offers to stop bombing in exchange for a productive peace treaty discussion.

  October: "March on the Pentagon"- antiwar demonstration.
  November: General Westmoreland promises a succesful outcome of the war.

Students protest against the Dow Chemical Company, a producer of napalm.

1967   US MILITARY FORCES IN VIETNAM- 500000
1968: January: Tet Offensive was launched against the South Vietnamese by the Viet Cong and the North Vietnamese, led by General Vo Nguyen Giap.
  February: The Battle for Hue lasts for 26 days as US and the PAVN forces try to recapture the cities seized by the Communists during the Tet Offensive.

General Westmoreland requests for 206000 additional troops but is rejected by Lyndon Johnson.

  March: My Lai Massacre takes place, led by Lt. Calley.

Lyndon Johnson suspends air bombing in some areas to ask North Vietnam for peace talks.

  May: US and North Vietnam agree to peace talks in Paris.
  October: Lyndon Johnson halts all bombing for peace talk.
  November: Richard Nixon becomes the presidents of US; Lyndon Johnson elects not to run for a second term.
1968   US MILITARY FORCES IN VIETNAM- 535000
1969: January: Negotiations in Paris takes place.
  Febuary: Bob Kerrey is sent on covert operation in Thanh Phong.
  March: US secretly bomb Cambodia to stop the  transport of supplies from North Vietnam to the Viet Congs on the Ho Chi Minh Trail.
  May: NLF peace plan demands unconditional US troops withdrawal and a coalition government in the South excluding Nguyen Van Thieu.
  June: Nixon orders 25000 troops to withdraw from Vietnam.
  September: Ho Chi Minh dies.

My Lai Massacre was revealed.

Formal charges were filed against Lt. Calley.

1969   US MILITARY FORCES IN VIETNAM- 475000
1970: May: Protests at Kent State University results in the death of four.
  June: US withdraw ground troops from Cambodia.
  December: Tonkin Gulf Resolution repealed.
1970   US MILITARY FORCES IN VIETNAM- 334000
1971: January: Cease-fire begins.
  March: Lieutenant William Calley is convicted of murder for the My Lai Massacre.
  May: Protests at Jackson State College results in the death of two.
  June: Pentagon Papers, submitted by Daniel Ellsberg, was first published on the New York Times
  October: Nguyen Van Thieu is reelected to presidency in South Vietnam.
1971   US MILITARY FORCES IN VIETNAM- 140000
1972: February: Nixon visits China.
  March: North Vietnam launches the Easter Offensive.
  April: Nixon orders bombing around Hanoi and Haiphong.
  May: North Vietnam captures Quang Tri City.
  June-Sept: South Vietnam, backed with the US air force, recaptures Quang Tri City.
  October: US and North Vietnam reaches a basis for the settlements but Nguyen Van Thieu disagrees with it.
  November: Nixon is reelected.

Nixon orders bombing in Hanoi-Haiphong area.

1972   US MILITARY FORCES IN VIETNAM- 24000
1973: January: Paris Peace Accords, negotiated by Le Duc Tho and Henry Kissinger, are signed.
  March: Last US troop leaves Vietnam.

US prisoners of war are released.

  August: US ends bombing in Cambodia.
1973   END OF VIETNAM WAR
Conclusion
1974: August: Nixon resigns; Gerald Ford becomes president.
1975:   Nguyen Van Thieu sent to exile.

Duong Van Minh becomes president of South Vietnam.

1976:   North Vietnam and South Vietnam are unified.