1US Especially in the West: (a name for) a saloon at the end of a street or the edge of a town. Now chiefly historical.
2Figurative and in figurative contexts. A final opportunity or hope for success; the last refuge of the unsuccessful or desperate. Now chiefly British.
last chance saloon/ˌlɑːs(t) tʃɑːns səˈluːn/ /ˌlas(t) ˌʃans səˈluːn/
Mid 19th century; earliest use found in Morning Republican (Little Rock, Arkansas). From last + chance + saloon.