Japan National Route 309

{{short description|National highway in Japan}}

{{onesource|date=January 2025}}

{{Infobox road

|country=JPN

|type=National

|route=309

|maint=

|alternate_name=

|map={{Maplink|frame=yes|plain=yes|zoom=|frame-align=center|frame-height=300|type=line|stroke-width=2}}

|map_custom=yes

|image=国道309号行者還トンネル.JPG

|length_km=145.5

|length_round=

|length_ref={{cite web|title=一般国道の路線別、都道府県別道路現況|trans-title=Road statistics by General National Highway route and prefecture|url=http://www.mlit.go.jp/road/ir/ir-data/tokei-nen/2016/pdf/d_genkyou26.pdf|language=ja|publisher=Ministry of Land, Infrastructure, Transport and Tourism|access-date=18 February 2020}}

|established=

|direction_a=

|terminus_a=

|junction=

|direction_b=

|terminus_b=

|previous_type=Route

|previous_route=308

|next_type=Route

|next_route=310

|browse=

}}

National Route 309 is a national highway of Japan connecting Kumano, Mie and Hirano-ku, Osaka in Japan, with a total length of 145.5 km (90.41 mi).