North of the Rio Grande is a 1937 American Western film directed by Nate Watt and written by Joseph O'Donnell. The film stars William Boyd, George "Gabby" Hayes, Russell Hayden, Morris Ankrum, Bernadene Hayes and Jack Rutherford. The film was released on June 25, 1937, by Paramount Pictures.

Plot

Hopalong Cassidy's Brother, Buddy, who appeared one time in Hopalong Cassidy Returns (1936), is shot in the back by the Deputy Sheriff Plunkett. His friend Lucky tries to testify against Plunkett but is thwarted by the crooked coroner Stoneham.. Lucky tells Buddy's wife, Mary, that he's dead...then tells her he's going to tell Hopalong Cassidy. Hoppy plans to enter town anonymously as an outlaw and work from that premise. Hoppy arrives posing as an outlaw to avenge his brother's killing by Plunkett. After robbing a train and killing Plunkett, he gets to meet the boss known as the Lone Wolf and lead his next job. Seeking help from Stoneman to capture the outlaws, he realizes too late that Stoneman is the Lone Wolf and is captured.