A plateau.
Not really. A plateau is an ELEVATED area of land with a flat or table like top. Your description (in your question) could also include a "plane" which is a large flat unelevated area of land.
a broad area of flat or gently rolling land is called a plain.
a plain
Plateau
Plateau
I think this answer is plain.
Plateau
I think this answer is plain.
Plateau
Plateau
Plateau
A Plateau.