Is marijuana the largest cash crop?

In production acreage, not even close. In street value, best estimates (since marijuana is, of course, illegal) indicate that it might be the second largest cash crop. Best estimates put the value at around $35.8 billion dollars, while corn, the largest, is valued at around $76 billion dollars. Soybeans, the next largest US cash crop in both value and acreage, is placed at around $35.7 billion dollars.