Postcode areas 42XXX
- Postcode area 42000 Saint-Étienne
- Postcode area 42100 Saint-Étienne
- Postcode area 42110 Feurs
- Postcode area 42111 Saint-Didier-sur-Rochefort
- Postcode area 42114 Chirassimont
- Postcode area 42120 Le Coteau
- Postcode area 42122 Saint-Marcel-de-Félines
- Postcode area 42123 Cordelle
- Postcode area 42130 Boën
- Postcode area 42131 La Valla-en-Gier
- Postcode area 42140 Chazelles-sur-Lyon
- Postcode area 42150 La Ricamarie
- Postcode area 42152 L'Horme
- Postcode area 42153 Riorges
- Postcode area 42155 Pouilly-les-Nonains
- Postcode area 42160 Andrézieux-Bouthéon
- Postcode area 42170 Saint-Just Saint-Rambert
- Postcode area 42190 Charlieu
- Postcode area 42210 Montrond-les-Bains
- Postcode area 42220 Bourg-Argental
- Postcode area 42230 Roche-la-Molière
- Postcode area 42240 Unieux
- Postcode area 42260 Saint-Germain-Laval
- Postcode area 42270 Saint-Priest-en-Jarez
- Postcode area 42290 Sorbiers
- Postcode area 42300 Roanne
- Postcode area 42310 La Pacaudière
- Postcode area 42320 La Grand Croix
- Postcode area 42330 Saint-Galmier
- Postcode area 42340 Veauche
- Postcode area 42350 La Talaudière
- Postcode area 42360 Panissières
- Postcode area 42370 Renaison
- Postcode area 42380 Saint-Bonnet-le-Château
- Postcode area 42390 Villars
- Postcode area 42400 Saint-Chamond
- Postcode area 42410 Pélussin
- Postcode area 42420 Lorette
- Postcode area 42430 Saint-Just-en-Chevalet
- Postcode area 42440 Noirétable
- Postcode area 42450 Sury-le-Comtal
- Postcode area 42460 Cuinzier
- Postcode area 42470 Saint-Symphorien-de-Lay
- Postcode area 42480 La Fouillouse
- Postcode area 42490 Fraisses
- Postcode area 42500 Le Chambon Feugerolles
- Postcode area 42510 Balbigny
- Postcode area 42520 Maclas
- Postcode area 42530 Saint-Genest-Lerpt
- Postcode area 42540 Saint-Just-la-Pendue
- Postcode area 42550 Usson-en-Forez
- Postcode area 42560 Saint-Jean-Soleymieux
- Postcode area 42570 Saint-Héand
- Postcode area 42580 L'Étrat
- Postcode area 42590 Neulise
- Postcode area 42600 Montbrison
- Postcode area 42610 Saint-Romain-le-Puy
- Postcode area 42620 Saint-Martin-d'Estréaux
- Postcode area 42630 Régny
- Postcode area 42640 Saint-Germain-Lespinasse
- Postcode area 42650 Saint-Jean-Bonnefonds
- Postcode area 42660 Saint-Genest-Malifaux
- Postcode area 42670 Belmont-de-la-Loire
- Postcode area 42680 Saint-Marcellin-en-Forez
- Postcode area 42700 Firminy
- Postcode area 42720 Pouilly-sous-Charlieu
- Postcode area 42740 Saint-Paul-en-Jarez
- Postcode area 42750 Saint-Denis-de-Cabanne
- Postcode area 42780 Violay
- Postcode area 42800 Rive-de-Gier
- Postcode area 42810 Rozier-en-Donzy
- Postcode area 42820 Ambierle
- Postcode area 42830 Saint-Priest-la-Prugne
- Postcode area 42840 Montagny
- Postcode area 42890 Sail-sous-Couzan
- Postcode area 42920 Chalmazel
- Postcode area 42940 Saint-Bonnet-le-Courreau
- Postcode area 42990 Saint-Georges-en-Couzan