Route national 309
|Route national 309 in France|
|Overall length:||77 km (historical: 1933-1973)
40 km (historical: 1973-1993)
Route nationale 309, N 309 or RN 309 for short, was a French national road.
The road was established in 1933 in two parts between Paris and Chantilly. The section between Sannois and Argenteuil originates from the N 14A. In 1973 the northern part was graded. In 1993 the rest of the route followed.
Route nationale 309A, abbreviated N 30 9A or RN 309A, was a side branch of the N 309 from 1933 to 1973, branching off from it at Carrefour des Bourguignons (in Asnières-sur-Seine and Bois-Colombes) and leading to national road 308 at Embranchement de Colombes (in Courbevoie and La Garenne-Colombes). In 1973 it was renumbered as national road 409 and in 1980 it was declassified as departmental road 11.