Mediterranean Sea
To the north of Pennsylvania, the state of New York borders its northern boundary. Additionally, Lake Erie forms part of Pennsylvania's northwestern border, while the southern shores of Lake Ontario are also within proximity to the northern part of Pennsylvania.
The Arctic Ocean is the northern boundary that surrounds the North Pole. This body of water is mostly covered by sea ice.
Thermocline.
Shoreline
Shoreline
Lake Erie is northwest of Pennsylvania.
"shore"
A natural boundary that is not a body of water could be formed by physical features such as mountains, deserts, or forests. These features act as barriers and define the limits of a region or country.
Raystown lake
black sea
black sea