Siberia Is Larger Than the Contiguous United States

Siberia: ~13.1 million km² (5.1 million mi²) – 77% of Russia.
Contiguous U.S.: ~9.83 million km² (3.8 million mi²).

Siberia exceeds the Lower 48 by roughly 33%. (Alaska adds ~1.7M km² to the U.S. total.)