Editing Interstate 129 (section)

{{Short description|Highway in Iowa and Nebraska}}
{{Use American English|date=April 2025}}
{{Use mdy dates|date=March 2015}}
{{Infobox road
|country=USA
|type=I
|route=129
|map={{maplink-road|from=Interstate 129.map}}
|map_custom=yes
|map_notes=I-129 highlighted in red
|length_mi=3.50
|length_ref=<ref name=NDOR>{{cite web|title=Nebraska Highway Reference Log Book|url=http://www.roads.nebraska.gov/media/6920/logbook.pdf|publisher=Nebraska Department of Roads|access-date=January 8, 2017|page=270|date=2015|archive-date=January 2, 2017|archive-url=https://web.archive.org/web/20170102171736/http://www.roads.nebraska.gov/media/6920/logbook.pdf|url-status=dead}}</ref><ref name=DOTGIS>{{cite web |title=Road Network (Portal) |url=https://gis.iowadot.gov/agshost/rest/services/RAMS/Road_Network/FeatureServer/0 |publisher=Iowa Department of Transportation |access-date=April 18, 2021 |location=Ames |format=[[ESRI shapefile]] |date=April 9, 2021}}</ref>
|length_notes=Nebraska: {{convert|3.21|mi|abbr=on}}<br>Iowa: {{convert|0.286|mi|m|abbr=on}}
|established=November 22, 1976<ref name="DOT Interstates">{{cite book|last=Iowa Department of Transportation|author-link=Iowa Department of Transportation|title=The National System of Interstate Defense Highways: 1956&ndash;1996}}</ref>
|direction_a=West
|terminus_a={{Jct|state=NE|US|20}} in [[South Sioux City, Nebraska]]
|junction={{Jct|state=NE|US|75|US|77}} in South Sioux City, Nebraska
|direction_b=East
|terminus_b={{Jct|state=IA|I|29|US|20|US|75}} in [[Sioux City, Iowa]]
|states={{flatlist|
*[[Nebraska]]
*[[Iowa]]
}}
|counties={{flatlist|
*'''NE'''
**[[Dakota County, Nebraska|Dakota]]
*'''IA'''
**[[Woodbury County, Iowa|Woodbury]]
}}
|browse={{ne browse|previous_type=NE|previous_route=128|route=[[List of Nebraska numbered highways|NE]]|next_type=NE|next_route=133}}{{ia browse|previous_type=IA|previous_route=128|route=[[List of state highways in Iowa|IA]]|next_type=IA|next_route=130}}
|spur_type=I
|spur_of=29
}}

'''Interstate&nbsp;129''' ('''I-129''') is an auxiliary Interstate Highway which connects [[South Sioux City, Nebraska]], to [[Interstate 29 in Iowa|I-29]] in [[Sioux City, Iowa]]. Opened in 1976, I-129 is a {{convert|3.5|mi|km|adj=mid|-long}} route, running {{convert|3.21|mi|km}} in [[Nebraska]]. At {{convert|0.286|mi|km}}, I-129 is the shortest highway in the state of Iowa. All of the route's length is concurrent with [[U.S. Route 20]] (US&nbsp;20) and most of its length is concurrent with [[U.S. Route 75|US&nbsp;75]].