Trinity Lens Casting Completed
Casting of the high-explosive lens components intended for the Trinity device is completed.
Permanent historical records · Updated 2026-11-03
1945 in United States of America — Page 4
Explore 287 historical events and records for United States of America in 1945.
Historical records for United States of America in 1945
Sorted by month and day. Records with no month are shown last. Showing 40 of 287 unique records.
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July
Gadget Assembly Begins
Assembly of the Trinity device, known as Gadget, begins as components are prepared for transfer to the test tower.
Gadget Raised to Test Tower
Gadget is hoisted to the top of the 100-foot Trinity test tower and its detonators are installed and connected.
Little Boy Components Shipped on Indianapolis
Little Boy bomb units and the uranium projectile leave San Francisco aboard USS Indianapolis for Tinian.
1st Nuclear Explosion
The first nuclear explosion, the "Trinity" test of an implosion-style plutonium-based nuclear weapon known as "the gadget", near Alamogordo, New Mexico
Bombing of Japan
General Carl Spaatz is ordered to bomb one of the targets: Hiroshima, Kokura, Niigata, or Nagasaki as soon as weather permitted, some time after August 3
Bombing of Japan
General Carl Spaatz is ordered to bomb one of the targets: Hiroshima, Kokura, Niigata, or Nagasaki as soon as weather permitted, some time after August 3
Bombing of Japan
General Carl Spaatz is ordered to bomb one of the targets: Hiroshima, Kokura, Niigata, or Nagasaki as soon as weather permitted, some time after August 3
first Nuclear Explosion
The joint work of the scientists at Los Alamos resulted in the first artificial nuclear explosion near Alamogordo on July 16, 1945, the site of which Oppenheimer named "Trinity". The first nuclear explosion, the "Trinity" test of an implosion-style plutonium-based nuclear weapon known as "the gadget", near Alamogordo, New Mexico
Gadget
The first nuclear explosion, the "Trinity" test of an implosion-style plutonium-based nuclear weapon known as "the gadget", near Alamogordo, New Mexico
Invention of Atomic Bomb
With Allied leaders in Potsdam when he hears news of the succesful test explosion
Manhattan Project
The first nuclear explosion, the "Trinity" test of an implosion-style plutonium-based nuclear weapon known as "the gadget", near Alamogordo, New Mexico
Manhattan Project
The joint work of the scientists at Los Alamos resulted in the first artificial nuclear explosion near Alamogordo on July 16, 1945, the site of which Oppenheimer named "Trinity". The first nuclear explosion, the "Trinity" test of an implosion-style plutonium-based nuclear weapon known as "the gadget", near Alamogordo, New Mexico
Manhattan Project
The first nuclear explosion, the "Trinity" test of an implosion-style plutonium-based nuclear weapon known as "the gadget", near Alamogordo, New Mexico
Manhattan Project
General Carl Spaatz is ordered to bomb one of the targets: Hiroshima, Kokura, Niigata, or Nagasaki as soon as weather permitted, some time after August 3
Manhattan Project
General Carl Spaatz is ordered to bomb one of the targets: Hiroshima, Kokura, Niigata, or Nagasaki as soon as weather permitted, some time after August 3
Manhattan Project
General Carl Spaatz is ordered to bomb one of the targets: Hiroshima, Kokura, Niigata, or Nagasaki as soon as weather permitted, some time after August 3
Manhattan Project
General Carl Spaatz is ordered to bomb one of the targets: Hiroshima, Kokura, Niigata, or Nagasaki as soon as weather permitted, some time after August 3
Nuclear Power
Witnesses the test nuclear explosion & says, "the war is over"
Trinity
The first nuclear explosion, the "Trinity" test of an implosion-style plutonium-based nuclear weapon known as "the gadget", near Alamogordo, New Mexico
Trinity Nuclear Test
The United States conducts the Trinity test, the first detonation of a nuclear explosive device.
Trinity Test Observation
Observes the Trinity nuclear test and performs a simple paper-drop experiment to make an immediate estimate of the explosion's yield.
Conference of Potsdam
Soviet power in Eastern Europe is recognized. Polands western frontier will follow the Oder-Neisse line. Germany will divided into 4 zones. Churchill, Stalin & Truman agree the map for post war Europe
1st Atomic Weapons
President Harry S. Truman discloses to Soviet leader Joseph Stalin that the United States has atomic weapons, Stalin feigns little surprise; he already knows this through espionage
Atomic Attack Directive Drafted
Groves drafts the directive authorising atomic attacks when bomb availability and weather permit, listing Hiroshima, Kokura, Niigata and Nagasaki.
Bombing of Hiroshima
Decides to drop the A-bomb on Hiroshima
Declaration of Potsdam
USA, Britain & Nationalist China calls for unconditional Japanese surrender. The US, Britain & Nationalist China calls for unconditional Japanese surrender
first Atomic weapons
President Harry S. Truman discloses to Soviet leader Joseph Stalin that the United States has atomic weapons, Stalin feigns little surprise; he already knows this through espionage
Manhattan Project
President Harry S. Truman discloses to Soviet leader Joseph Stalin that the United States has atomic weapons, Stalin feigns little surprise; he already knows this through espionage
Ultimatum-Potsdam
The Japanese have to choose "utter devastation or unconditional surrender"
Bretton Woods Agreements Act
Truman signs legislation authorising United States participation in the IMF and World Bank, implementing the institutions supporting the new dollar-gold monetary order.
Little Boy Assembly Completed
Final assembly of Little Boy is completed on Tinian and the weapon is ready for combat use.
August
Fat Man Assembly Begins on Tinian
Fat Man bomb cases arrive on Tinian and assembly of the plutonium implosion weapon begins.
Bombing of Hiroshima
"Little Boy" is loaded onto the Enola Gay
Enola Gay Named
Tibbets names B-29 number 82 Enola Gay and receives final confirmation for the Hiroshima mission scheduled for the next day.
Bombing of Hiroshima
A co-pilot on the Enola gay which drops the "little boy" a-bomb on Hiroshima
Bombing of Hiroshima
"Little Boy", a gun-type uranium-235 weapon, is used against the city of Hiroshima, Japan
Bombing of Hiroshima
"Little Boy", a gun-type uranium-235 weapon, is used against the city of Hiroshima, Japan
Bombing of Hiroshima
Commands US strategic air forces using the uranium weapon.
Bombing of Hiroshima
Flies the "Enola Gay" which drops an atomic bomb on Hiroshima
How these records were prepared
Generated from the World History Database historical_events table. Identical display records are collapsed; descriptions otherwise retain the stored text. Coverage and source quality vary. Check primary and specialist sources before citing individual historical claims.