"Mendocino County Line" is a song written by Matt Serletic and Bernie Taupin, and recorded as a duet by American country music artists Willie Nelson and Lee Ann Womack.

It was released in January 2002 as the lead-off single from Nelson's album The Great Divide.

Deborah Evans Price, of Billboard magazine reviewed the song favorably, saying that when Womack sings the chorus, "there's a tender, almost epic feeling to her heartache."

Regarding Nelson, she states that he "imbues each line with the kind of emotional integrity that has become his trademark."

"[2] Mario Tarradel of The Dallas Morning News described the song and wrote, "They do sound good together; their voices complement each other like leather softened by lace.