Following a northwest-southeast axis perpendicular to the St. Lawrence River, the A-73 provides an important freeway link with regions north and south of Quebec City, the capital of the province.

Civic, political, and business leaders in regions north and south of the A-73's termini have lobbied the Quebec government to extend the autoroute.

Approaching metropolitan Quebec City, the A-73 meets the A-20 (co-signed as a section of the Trans-Canada Highway) at an interchange just south of the Saint Lawrence River.

From here, motorists can take the A-20 east to Rivière-du-Loup, Rimouski, and the Gaspé Peninsula; and west to Montreal, Toronto, and Ottawa (via the A-40 and Ontario Highway 417).

The A-73/40 continues north for three kilometres to a junction with Autoroute 573, a spur route that provides access to the CFB Valcartier military base.

(This anomaly reflects an unbuilt section of the A-40, which would have started at Saint-Augustin-de-Desmaures, bypassed Jean-Lesage Airport to the north, and connected with the present-day A-73/40 at the A-573 interchange.)

[1] The road continues as Route 175, which provides a link between Quebec City and the Saguenay-Lac-Saint-Jean region to the north (remaining as a freeway through kilometre 184, although that is not signed as A-73).

[3] The issue resurfaced during a 2015 by-elections in Beauce-Sud, when Coalition Avenir Québec leader François Legault announced his support for extending the A-73 to Maine as a priority for his party if elected.

Between 2003 and 2013, the governments of Quebec and Canada co-funded reconstruction of Route 175 into a partially-controlled access freeway between the end of A-73 in Stoneham and the junction with the A-70 in Saguenay.

As the reconstructed Route 175 (except for the first 17 km north of the current A-73 terminus) is not fully a controlled-access highway, it does not meet Autoroute design standards.