This peak has at least two known routes, both climbed in 1991.

But I would not follow a known route.

There were actually as many as 50 groups, taking one of seven known routes.

There are at least 16 known routes to the summit which have different difficulties.

He held the only two known routes into Deep Creek, but the enemy held the whip hand.

Nor do its "directions" conform to any known underground route.

And there was no other known route to safety.

These dates agree with data derived from blood transfusions and other known routes of transmission.

You could go only so far on the Skyway before the known routes were exhausted.

It provided information to all interstellar vessels, both military and civilian, regarding the potentially hazardous spots along known routes.