Its the Bering Strait. The Bering Strait and Bering Sea separate the landmasses of Asia and North America, as well as forming the international boundary between Russia and the United States. This national and continental boundary separates the Diomede Islands in the Bering Strait, with Big Diomede in Russia and Little Diomede in the US.
The closest point between the Asian and North American continents is the Bering Strait, which is about 55 miles (88 kilometers) wide. This narrow body of water separates Russia (Asia) from Alaska (North America).
Asia. (Alaska and Russia are only about 5 miles apart at the Bering Strait)
Asia and South America
North America, Europe, and Asia are the three continents closest to the North Pole.
South America and Asia.
South America
The two closest continents to Hawaii are North America and Asia. North America is about 2,500 miles away, while Asia is around 3,850 miles away from Hawaii.
Europe and Africa both touch Asia. North America is the closest without physical contact.
Asia and Australia
Asia is closer to the US, I believe at the closest Russia and Alaska are 5 kilometres apart. However, if you mean the contiguous US (lower 48), then Europe is closer. Asia and the West Coast are about 8260 kilometres apart, and the East Coast and Europe are about 5440 kilometres apart.
Asia is the continent closest to California. Specifically, the closest point in Asia to California is the eastern coast of Russia, which lies across the Bering Strait from Alaska.
North America and Asia are the nearest neighbors to each other, with the Bering Strait separating them by only about 55 miles at their closest point.