Question

the lands upon the river ohio are . . . known to be the property of the crown of great britain. . . . it is a matter of equal concern and surprise to me to hear that . . . french forces are erecting fortresses and making settlements upon that river, within his majestys domains. . . . in obedience with my instructions, it becomes my duty to require your peaceable departure. erecting: building domains: territory peaceable: peaceful based on the letter, what was george washingtons mission? to help the french force native americans out of the area to order the french to leave the area to teach the french how to construct fortresses to start a war with france for the ohio river valley

Explanation:

The text states that the lands on the River Ohio are the property of the Crown of Great Britain and that French forces are building fortresses and making settlements there. It then says "In obedience with my instructions, it becomes my duty to require your peaceable departure." This indicates the mission is to order the French to leave the area.

Answer:

To order the French to leave the area