The lowest layer of the Atmosphere, 6 miles (10 km) in some places and as much as 12 miles (20 km) in other places. This is where all the weather occurs.
The troposphere is the layer next to the ground or surface of the Earth. It covers around 30,000-50,000 feet high. This is where we live and even where planes fly. Around 80% of the mass of the atmosphere is in the troposphere. The troposphere is heated by the surface of the Earth.