Step 1: Categories. Forest Survey of India (FSI) reports classify states by total forest area. Step 2: Largest state-wise cover. Madhya Pradesh has the largest area under forest cover, though Arunachal Pradesh has the largest percentage of forest cover relative to its area. Step 3: Conclude. Thus, by area, Madhya Pradesh ranks first.
\[
\boxed{\text{Madhya Pradesh}}
\]