The actual body of water is the biggest one.
Apache Indians are causing major problems for Lt. Col. Kirby Yorke (John Wayne) and his United States cavalry troops. But his orders stop him from pursuing the Apache when they cross the Rio Grande into Mexico, and safety.
Plenty of symbolic crossings have to be made too. Yorke's estrangement from his wife, Kathleen (Maureen O'Hara), is long-standing. He hasn't seen his son, Jeff (Claude Jarman, Jr.) in 15 years. The younger Yorke wants to serve in the military too, but he fails at West Point. Instead, he enlists in the cavalry and is posted as a trooper to serve under his father. He's with two other new recruits - Travis Tyree (Ben Johnson) and Sandy Boone (Claude Jarman).
Kathleen shows up because she wants to get her son out of the service. Neither he, or Kirby, agree with her mission.
"What kind of man is he?" Jeff asks his mother of Kirby.
"He's a very lonely man," she replies.
Tyree is wanted by a deputy federal marshal (Grant Withers) for manslaughter. He's on his own journey too. Will he be taken into custody or make a bid for freedom?
Rio Grande
The most impressive action scene in this film isn't a battle between the Apache and cavalry, but a training sequence when troopers stand, and ride, two horses. This long-time movie fan has never seen such a stunt before. It's jaw-dropping viewing.
Sons of the Pioneers make several welcome appearances with low-key music that enhances the film's mood, especially a romantic tune when Kirby and Kathleen first dine together.
Military folly was explored in Fort Apache
Rio Grande
RATING: 8/10
FUN FACTS: Hey, that's Karolyn Grimes, Zuzu Bailey from It's a Wonderful Life
J. Carrol Naish, who appears as Lt. Gen. Philip Sheridan, made his last screen appearance in Dracula vs. Frankenstein.
Sons of the Pioneers appeared in nearly 100 films and television shows between 1934 and 1984.