| Province: | QC |
| Type: | Autoroute |
| Route: | 640 |
| Alternate Name: | Autoroute 640 |
| Maint: | Transports Québec |
| Map Custom: | yes |
| Map Notes: | Map of Greater Montreal with the A-640 in red |
| Length Km: | 53.2 |
| Length Round: | 1 |
| Length Ref: | [1] [2] |
| Direction A: | West |
| Terminus A: | in Oka |
| Junction: | in Boisbriand in Sainte-Thérèse in Charlemagne |
| Direction B: | East |
| Terminus B: | in Charlemagne |
| Established: | 1961[3] |
| Cities: | Terrebonne, Blainville, Saint-Eustache, Mascouche, Boisbriand |
| Previous Type: | A |
| Previous Route: | 610 |
| Next Type: | A |
| Next Route: | 730 |
Autoroute 640 (or A-640) is a Quebec autoroute that runs across the North Shore Region (paralleling the Rivière des Mille-Îles) from Route 344 in the Oka area to Route 138, where it ends as a four-lane expressway in Charlemagne. The road was designed to be northern bypass of the city of Montréal and was originally intended to cross the Lake of Two Mountains to connect to Autoroute 40 near Vaudreuil. It is currently 54.81NaN1 long.
A-640 begins at Chemin d'Oka (Route 344) at a traffic circle near Oka National Park, and terminates at a signalized at-grade intersection with Rue Émile-Despins (Route 344) in Charlemagne.
A-640 was built over the following timeline: