Marlboro country, n. — Green’s Dictionary of Slang

Marlboro country n.

[suggested by the landscapes featured in advertisements for Marlboro cigarettes]

(US) the remote countryside.

1968		R. Gover JC Saves (1979) 66: Sure is marlboro country. Ain’t a soul in sight.
1970		Harper’s Mag. Aug. 39: One of the good things about Marlboro country and such, where men are men and pack something...to prove it [HDAS].
1982		(con. 1960s) S. Dunstan Vietnam Tracks 121: In the ‘Marlboro Country’ west of An Khe.