Final answer:
The Ohio River Valley was the region in North America that caused conflict between France and Great Britain leading to the French and Indian War. Both powers claimed the area, resulting in military engagements that escalated into the broader conflict.
Step-by-step explanation:
The region that became a cause of conflict between France and Great Britain before the French and Indian War was the Ohio River Valley. The British colonies were expanding in population and Virginia planters faced stagnant tobacco prices.
They hoped that expanding into the western lands would improve their wealth and status. The Ohio Company of Virginia was formed and was granted half a million acres by the British crown in 1749.
However, the French also laid claim to this land and established Fort Duquesne in 1754 to assert their control. This rivalry set the stage for the French and Indian War (1754-63), part of the global Seven Years' War, making the Ohio River Valley a significant area of contention between the colonial powers and their Native American allies.