Final answer:
The Allegheny Plateau is located on the eastern portion of Pennsylvania and is part of the broader Appalachian Plateau region, known for its preserved fossils and geological resources such as coal.
Step-by-step explanation:
The state that has the Allegheny Plateau on the eastern portion of it is Pennsylvania. This region includes part of the Appalachian Plateau and is known for its rugged terrain, which extends into Pennsylvania from the south and west. Notably, the rocks of the Appalachian Plateau are similar in age and lithology to those in the Valley and Ridge province. However, the Allegheny Plateau has better preservation of fossils due to the relative lack of extensive folding and faulting. Moreover, Pennsylvania's Allegheny Plateau is rich in geological resources, such as coal. Pennsylvania's location at the heart of Appalachian geology makes it a central area for understanding past orogenic events, like the Alleghenian Orogeny, which shaped much of the eastern United States' mountainous terrain.