| Country: | NZL |
| Type: | SH |
| Route: | 40 |
| Maint: | New Plymouth District Council, Ruapehu District Council |
| Decommissioned: | 1991 |
| Length Km: | 89 |
| Direction A: | West |
| Direction B: | East |
| Terminus A: | Ahititi |
| Terminus B: | Mangatupoto |
| Destinations: | Okau, Kotara, Waitaanga, Ōhura, Nihonihu, Matiere, Tuhua, Ongarue Electric Substation |
| Previous Type: | SH |
| Previous Route: | 39 |
| Next Type: | SH |
| Next Route: | 41 |
State Highway 40 was part of the New Zealand state highway network before it was revoked in 1991–92.[1] [2]
SH 40 left at the small locality of Ahititi, north of New Plymouth. The route follows the Tongaporutu River and its tributaries, passing through the high King Country hills and the locality of Kotare. After Waitaanga, the road passes over the Waitaanga saddle and enters the Ōhura River valley. At Ōhura, old intersects with SH 40 at a TOTSO junction. It follows the Stratford to Okahukura Line along with the Ōhura River until Tuhua, after passing through Nihoniho and Matiere. From Tuhua, the road runs alongside the river and a major electricity pylon line past the Ongarue Substation until the intersection with at Mangatupoto.