Context: Oklahoma City lies in the Sandstone Hills region of Oklahoma, known for hills of 250 to 400 feet (120 m) and two species of oak: blackjack oak (Quercus marilandica) and post oak (Q. stellata). The northeastern part of the city and its eastern suburbs fall into an ecological region known as the Cross Timbers.

Question: Which region is Oklahoma city located in?

Answer: Sandstone Hills region