It is the third installment of Ford's "Cavalry Trilogy", following two RKO Pictures releases: Fort Apache (1948) and She Wore a Yellow Ribbon (1949).

[a] Rio Grande's supporting cast features Ben Johnson, Claude Jarman Jr., Harry Carey Jr., Chill Wills, J. Carrol Naish, Victor McLaglen, Grant Withers, the Western singing group the Sons of the Pioneers and Stan Jones.

In contrast to its one-sided portrayal of Native Americans, its treatment of the reconciliation of an estranged couple and their son is emotionally complex.

In the summer of 1879, Lieutenant Colonel Kirby Yorke is posted on the Texas frontier in command of the 2nd U.S. Cavalry Regiment to defend settlers against attacks by marauding Apaches.

In a meeting with his father, Yorke informs him that he will receive no special treatment in the brutal way of life he has chosen; Jeff declares he wants none.

Sheridan has decided to order Yorke to cross the Rio Grande into Mexico in pursuit of the Apaches and kill them all, an action with serious political implications.

Before Yorke leads his men toward Mexico, he sends the women and children to Ft. Bliss for safety, with an escort including Jeff.

After Colonel Yorke recovers, Troopers Tyree, Boone, Jeff, Corporal Bell, and Indian Scout Son of Many Mules are decorated.

At the ceremony, when one of the Texas marshals reappears Trooper Tyree continues his run from the law, stealing General Sheridan's horse for the purpose.

Instead, he wanted to film the Ireland-set romantic comedy-drama film The Quiet Man with Wayne and Maureen O'Hara, but Herbert Yates, the studio president of Republic Pictures, insisted that Ford first make Rio Grande with the same pairing of Wayne and O'Hara because he thought the script of The Quiet Man was weak and that the story was of little general interest.

It is based on a short story "Mission With No Record" by James Bellah that appeared in The Saturday Evening Post on September 27, 1947.

Colonel Ranald Mackenzie, under orders from General Phil Sheridan, crossed the border to fight Kickapoo people, and kidnapped some of their women and children to hold as hostages.

[16] Rio Grande was the first of three films directed by Ford starring the pairing of John Wayne and Maureen O'Hara, followed by The Quiet Man in 1952[17] and The Wings of Eagles in 1957.

[18] O'Hara recalled that the weather was so hot that production crew dug a pit covered by a tarp to have a cooler resting place.

[26] William Brogdon at Variety summarized the film as "big brawling mass action clashes, mixed together with a substantial portion of good, honest sentiment" which predict box office success.

[4] Garry Wills's 1997 book, John Wayne's America, called Rio Grande the "most beautifully filmed" of the Cavalry trilogy.

He attributed this to the landscape in Moab, the sensitivity of the cinematographers, and intimate tent scenes that emphasize emotion on actors' faces.

"[29] In contrast to earlier Westerns, which emphasized a lone ranger, Slotkin described Yorke's leadership style as "professionally irregular": enforcing discipline and the chain of command while adapting to the changing needs of war.

[30] In a biography of John Wayne, authors Randy Roberts and James S. Olson analyze the success of Rio Grande, alluding to consensus that it was the weakest film in the cavalry trilogy.

They related the film's central conflict of "the frustration of diplomatic niceties and the untenable nature of borders" to the beginning of the Korean War, which involved American soldiers defending against Chinese attackers in North Korea.

Roberts and Olson wrote that this solution reflected the conservative politics of Bellah and McGuinness, who believed that America's enemies who kill innocent people should be pursued into neutral countries if they take refuge there.

[2] In a book on Ford, Wayne, and Ward Bond, Scott Allen Nollen also noticed that Rio Grande's "reactionary attitude toward Apaches as simplistic savages reflect[ed]" the "arch-conservative" views of McGuinness.

He wrote that the river in Rio Grande is "a Yalu or Iron Curtain, which can only be crossed in arms for battles of rescue and/or annihilation.

Joseph Breen, acting under the Production Code Administration, said the script was "blatantly racist" and asked the producers to cut some of the more egregious lines, which they did.

[35][36] McBride called it Ford's first "mature love story," where the "emotionally complex family drama [...] elevat[es] Rio Grande above its crudely racist and stridently jingoistic military plot."

For Classical Hollywood film scholars Gaylyn Studlar and Matthew Bernstein,[37] the emotional theme for both Kathleen and Yorke is that they "must confront and resolve the tension between the demands of duty and the love of family."

"[15] When Yorke returns, injured on a stretcher, Kathleen publicly walks alongside him, holding his hand, making her decision to stay with him one that includes the entire fort community, where women share in suffering while their husbands fight.

[39] While Kathleen's role is limited, she still represents a greater feminine presence than in many other westerns, such as those by Howard Hawks, Anthony Mann, or John Sturges.

[40] Rio Grande's western family drama shows, for Meeuf, "the dynamic tensions of the balance between masculine adventurism and a settled domestic existence".

Kathleen initially wants to take her son back home with her so that he can be tutored in mathematics (the subject he failed) and return to West Point, where he can get a commission as an officer.