Relations between the Soviet Union and the United States were fully established in 1933 as the succeeding bilateral ties to those between the Russian Empire and the United States, which lasted from 1776 until 1917; they were also the predecessor to the current bilateral ties between the Russian Federation and the United States that began in 1992 after the end of the Cold War. The relationship between the Soviet Union and the United States was largely defined by mistrust and tense hostility. The invasion of the Soviet Union by Germany as well as the attack on the U.S. Pacific Fleet at Pearl Harbor by Imperial Japan marked the Soviet and American entries into World War II on the side of the Allies in June and December 1941, respectively. As the Soviet–American alliance against the Axis came to an end following the Allied victory in 1945, the first signs of post-war mistrust and hostility began to immediately appear between the two countries, as the Soviet Union militarily occupied Eastern European countries and turned them into satellite states, forming the Eastern Bloc. These bilateral tensions escalated into the Cold War, a decades-long period of tense hostile relations with short phases of détente that ended after the collapse of the Soviet Union and emergence of the present-day Russian Federation at the end of 1991.

The Union of Soviet Socialist Republics (USSR), commonly known as the Soviet Union, was a transcontinental country that spanned much of Eurasia from 1922 to 1991. It was the largest country in the world by area, extending across eleven time zones and sharing land borders with twelve countries. A successor state to the Russian Empire, the country was nominally organized as a federal union of fifteen national republics, the largest and most populous of which was the Russian SFSR; in practice both its government and economy were highly centralized until its final years. It was the world's third-most populous country and Europe's most populous country. As a one-party state governed by the Communist Party of the Soviet Union, it was a flagship communist state. Its capital as well its largest city was Moscow. Other highly urbanized centers were Leningrad, Kiev, Tashkent and Baku.