Which battle in 1777 is considered the turning point of the war?

The battle in 1777 considered the turning point of the American Revolutionary War was the Battle of Saratoga.

Saratoga was actually a campaign consisting of two major battles near Saratoga, New York: Freeman's Farm on September 19 and Bemis Heights on October 7. American forces commanded by Horatio Gates, with important battlefield contributions from Benedict Arnold and others, stopped British General John Burgoyne's attempt to move south from Canada and control the Hudson River Valley.

Burgoyne surrendered his army on October 17, 1777. The victory mattered far beyond the battlefield because it convinced France that the American cause had a realistic chance of success. France then entered a formal alliance with the United States, supplying troops, weapons, loans, and naval support. French assistance later proved crucial at Yorktown.

The other choices were genuine Revolutionary War battles, but none had Saratoga's combination of strategic impact and diplomatic consequences. The battle did not end the war; fighting continued for several years, and the final major land engagement came at Yorktown in 1781.