Ōtira River

{{Short description|River in the South Island of New Zealand}}

{{Use dmy dates|date=July 2019}}

{{Use New Zealand English|date=March 2024}}

{{Infobox river

| name = Ōtira River

| image = Arthur's Pass.jpg

| image_size =

| image_caption = Upper Ōtira River and Ōtira Viaduct

| map = {{Maplink|frame=yes|type=line|plain=yes|zoom=10|frame-align=center|frame-width=270|frame-height=270|stroke-color=#0000ff|stroke-width=2}}

| map_size =

| map_caption = Route of the Ōtira River

| map_alt =

| pushpin_map = New Zealand#New Zealand South Island

| pushpin_map_size = 270px

| pushpin_map_caption = Mouth of the Ōtira River

| pushpin_map_alt =

| source1 = Mount Rolleston

| source1_location =

| source1_coordinates = {{coord|-42.9022|171.5231|type:river_region:NZ|display=inline}}

| source1_elevation =

| mouth_location = Taramakau River

| mouth_elevation =

| mouth_coordinates = {{coord|-42.762|171.633|region:NZ|format=dms|display=inline,title}}

| subdivision_type1 = Country

| subdivision_name1 = New Zealand

| length = {{convert|20|km|abbr=on}}

| discharge1_avg =

| basin_size =

| progression = Ōtira River → Taramakau River → Tasman Sea

| tributaries_left = Curtis Creek, Kea Creek, Park Creek, Hodge Creek, Rolleston River, Goat Creek, Kellys Creek

| tributaries_right = Pegleg Creek, Candys Creek, Reid Falls, Wesley Creek, Barrack Creek, Deception River, Paratu Stream

| waterfalls =

| bridges = Ōtira Viaduct, Wallace Point Bridge, Yorkeys Point Bridge, Ōtira River Bridge, Morrison Footbridge

}}

The Ōtira River is located in the central South Island of New Zealand. It rises on the slopes of Mount Rolleston in the Southern Alps, and flows north for {{convert|20|km}}, passing through the town of Otira before joining the Taramakau River.{{LINZ|id=34568|name=Ōtira River|access-date=20 December 2020}}

The Taramakau's outflow is into the Tasman Sea, {{convert|12|km}} south of Greymouth.

The valley of the Ōtira River forms the northwestern approach to Arthur's Pass, one of the three main passes across the Southern Alps.