Who were the primary nations involved in the Allies during World War II?

The primary nations involved in the Allies during World War II were the United States, the United Kingdom, the Soviet Union, and China. These countries formed a coalition to combat the Axis powers, which consisted mainly of Germany, Italy, and Japan.

The United States provided significant military and industrial support, fundamentally transforming the war's dynamics after its entry in 1941. The United Kingdom, having faced the brunt of the war from the outset, was a key player in European combat efforts. The Soviet Union, initially bound by a non-aggression pact with Germany, joined the Allies after being invaded in 1941, contributing significantly to the Eastern Front and ultimately to the defeat of Nazi Germany. China, engaged in conflict with Japan prior to the formal commencement of World War II, played a crucial role in tying down Japanese forces.

Other groups listed, such as the ones involving Germany and its allies or nations from earlier conflicts, do not reflect the coalition formed specifically against the Axis during World War II.