The Walsh Lake watershed is mainly served on the east side by the route 175 which links the towns of Quebec and Saguenay.

A few secondary roads serve this area for forestry and recreational tourism activities, notably forest road 12 which runs north of the lake and in the area between Fragasso Lake and lac Walsh.

[2] A water regulation dam was built in 2005 at the mouth of Walsh Lake allowing a water retention height of 2.4 metres (7 ft 10 in) for a reservoir capacity of 816,000 metres (2,677,165.354 ft).

Then, the current from the latter crosses 2.7 kilometres (1.7 mi) to the west of the Lac des Alliés to its mouth.

The toponym "Lac Walsh" was formalized on June 1, 1971, by the Commission de toponymie du Québec.