Dec 8th 1941 the day after Pearl Harbor
1 September 1939. After Germany invaded Poland. France and the United Kingdom thereby declared war on Germany, signalling the beginning of the Second World War.
The U.S. has formally declared war five sepate times: War of 1812, Mexican-American War, Spanish-American War, World War I, and World War II.During World War II the U.S. declared war against Japan on December 8, 1941, Germany and Italy on December 11, 1941, Bulgaria, Hungary and Romania on June 5, 1942.
I will only list the more important countries involved in the war because there were many minor countries that are of very little importance to the war.Austria-Hungary declared war on Serbia July 28 1914Russia declared war on Austria-Hungary July 30 1914Germany declared war on Russia August 1 1914Germany declared war on France August 3 1914Germany declared war on Belgium August 4 1914Britain declared war on Germany August 4 1914Montenegro declared war on Austria-Hungary August 5 1914Serbia declared war on Germany August 6 1914Montenegro declared war on August 9 1914France declared war on Austria-Hungary August 11 1914Britain declared war on Austria-Hungary August 12 1914Austria-Hungary declared war on Belgium August 22 1914Japan declared war on Germany August 23 1914Japan declared war on Austria-Hungary August 25 1914Russia declared war on Ottoman Empire November 1 1914Serbia declared war on Ottoman Empire November 2 1914Montenegro declared war on Ottoman Empire November 3 1914Britain declared war on Ottoman Empire November 5 1914France declared war on Ottoman Empire November 5 1914Italy declared war on Austria-Hungary May 23 1915Italy declared war on Ottoman Empire August 21 1915Bulgaria declared war on Serbia October 14 1915Britain declared war on Bulgaria October 15 1915Montenegro declared war on Bulgaria October 15 1915France declared war on Bulgaria October 16 1915Italy declared war on Bulgaria October 19 1915Russia declared war on Bulgaria October 19 1915Romania declared war on Austria-Hungary August 27 1916Italy declared war on Germany August 27 1916Germany declared war on Romania August 28 1916Ottoman Empire declared war on Romania August 20 1916Bulgaria declared war on Romania September 1 1916United States declared war on Germany April 6 1917United States declared war on Austria-Hungary December 7 1917The Armistice occurred November 18 1918Note: where Britain is listed, this includes declarations of war by British Dominions also(Canada, Australia, New Zealand, South Africa and India), as they were not completely independent during the First World War and couldn't conduct Foreign Policy themselves.
europe
December 7th, 1941
December 12, 1941
1948/
They declared war on Germany with France. I don't know the date.
The US declared war on Germany, hour after Germany declared war on the US on December 11, 1941.
September, 2 1945
The US declared war on Germany on Dec 11th 1941, (two days after Germany declared war on the US). Everything since that date to the present is after.
War was declared.
December 7th, 1945 That is World War II. On April 6, 1917, the United States declared war on Germany during World War I.
WW2 was the last declared war fought by the US.
no the beginning of the second world war (ww2) was the 1st of September 1939 when Germany invaded Poland Britain and France declared war !!!
President Woodrow Wilson declared war on Germany in World War I on April 6, 1917.
no, japan did not formally declare war Germany declared war on u.s. after u.s. declared war on japan