The northernmost point of the Antarctic continent is Prime Head at 63° 12' 48" S, 57° 18' 8" W. All land south of 60 degrees S is governed by the Antarctic Treaty.
So, you could say that both 63 degrees S and 60 degrees S -- lines of latitude -- form a northern boundary of Antarctica: your choice.
The imaginary line that forms the northern boundary of most of Antarctica is the Antarctic Circle, located at approximately 66.5 degrees south latitude. Beyond this line, there are restrictions on sunlight and daylight hours due to the tilt of the Earth's axis.
the country that forms the northern boundary of the United States is Canada :)
This is the boundary with Ukraine: mountains and the river Tisa.
The sea that forms the northern boundary of Africa is the Mediterranean Sea. The countries of Morocco, Algeria, Tunisia, Libya and Egypt border it.
No. Antarctica is the southern-most continent on earth. Parts of northern Canada are the northern-most land forms on earth.
The Arctic Ocean
red river
Both Chile and Argentina, close to Antarctica.
The sea that forms the northern boundary of Africa is the Mediterranean Sea. The countries of Morocco, Algeria, Tunisia, Libya and Egypt border it.
Most of the northern boundary is formed by the Alps. However, on the Iberian Peninsula, the Pyrenees form another northern border of Southern Europe.
Mediterranean Sea
The river Danube and the South Dobrogea.