The sea.
The Mississippi River helped form the boundary between British and Spanish territory in 1763.
British territory surrounded the globe. there was no western boundary.
The Ohio river
The Appalachian Mountains became the western boundary of the British colonies.
Mississippi River
Appalachian mountains
The Appalachian Mountains.A wall of Mountains The 1,500-mile- long Appalachian Mountain range formed a natural barrier to westward expansion.
The Appalachian Mountains marked the western boundary of British claims.
The Mississippi River marked the eastern boundary of Spanish territory in North America during the colonial period.
Its the Ural Mountains in Russia
Hugh
It is the British Naval Base at Gibraltar. The Rock of Gibraltar being the famous physical feature.