Final answer:
The British land south of Washington D.C. stemmed from political decisions marked by historical events like the French and Indian War and the Royal Proclamation of 1763, which restricted colonial expansion westward and led to tensions that contributed to the American Revolution.
Step-by-step explanation:
The cause of British land 25 miles south of Washington D.C. can be attributed to political decisions influenced by various historical events, particularly in the colonial and Revolutionary era. The war for control over North American territories, such as the French and Indian War, as well as land hunger among British colonists, led to escalating border disputes driving expansion toward modern-day Maine and beyond. Specifically, the Royal Proclamation of 1763, a political decision made by the British Crown, established a boundary to restrict colonial expansion beyond the Appalachian Mountains, which was a source of great frustration among colonists and land speculators alike.
Land speculators, including figures such as George Washington, were eager to invest in new lands as a means to diversify economic activities beyond conventional crops like tobacco, which were experiencing stagnated prices and depleted soil fertility. The incessant drive to expand territory led to increased tensions with Native American tribes, who were defending their lands from colonial encroachment. Consequently, the appetite for westward expansion and land was a contributing factor to the underlying causes of the American Revolution.