On what date did Apollo 11 leave lunar orbit for Earth?

Apollo 11 left lunar orbit for Earth on July 22, 1969.

The spacecraft entered lunar orbit on July 19, and Michael Collins, Neil Armstrong, and Buzz Aldrin spent roughly a day and a half operating around the Moon. Armstrong and Aldrin first landed in the Lunar Module Eagle, then lifted off from the surface on July 21 and rendezvoused with Collins aboard the Command Module Columbia.

The crew departed lunar orbit at 04:55:42 UTC on July 22, when Columbia’s service propulsion engine performed the trans-Earth injection burn. This maneuver placed Apollo 11 on a return trajectory toward Earth. The spacecraft then spent several days crossing cislunar space before splashing down in the Pacific Ocean on July 24.

July 20 is commonly associated with Apollo 11 because it was the date of the lunar landing in Universal Time, while July 21 was the date in many locations when Armstrong stepped onto the surface. Neither date is the departure from lunar orbit; that occurred on July 22.