“Once again John Wayne plays Kirby York, only this time he's a Lt.-Colonel - presumably promoted from Captain thanks to his heroic actions in Fort Apache. York is married, though estranged from his wife, and the film begins when the son he hasn't seen for 15 years arrives at the post as an enlisted man, fresh from flunking out of West Point. The tensions between Wayne's military duties and his family life foreshadow some of the themes Ford and Spig Wead would rework (to better effect) in The Wings of Eagles. Critical opinion generally ranks Rio Grande as the least important film of the Trilogy, but Sarris includes it as one of six films he feels are ‘Ford's most profound achievements in his late period as film poet without portfolio.'” --Michael Goodwin