1. D layer: This is the lowest layer, extending from about 50 to 90 km in altitude.

2. E layer: This layer lies above the D layer, from about 90 to 130 km in altitude.

3. F layer: This is the highest layer, extending from about 130 to 600 km in altitude. The F layer is further divided into two sublayers: F1 and F2. The F2 layer is the densest and most important layer for radio communications.