Route nationale 1b (Madagascar)

{{Short description|Road in Madagascar}}

{{Infobox road

| country = MDG

| type = RN

| route = 1 bis

| map =

| length_mi =

| length_km = 94

| length_ref =

| established =

| direction_a =

| terminus_a = Analavory

| junction =

| direction_b =

| terminus_b =Tsiroanomandidy

| previous_type =

| previous_route =

| next_type =

| next_route =

}}

Route nationale 1b (RN 1bis) is a secondary highway in Madagascar of 94 km, running from Analavory to Tsiroanomandidy. It crosses the region of Bongolava and Itasy.