The only lake I know of with Tagus in it's name, is Tagus Crater Lake on the island of Isabela in the Galapagos Islands.

There is also a Tagus River that flows through Spain and Portugal.

the length of the Tajo river is actually 1,038 km but it is actually called Tagus

It is in Spain and Portugal shares the tagus river with Spain....but it is mostly about Spain:d

Yes. Spain and Portugal share the Iberian Peninsula. They also share the Tagus [Tejo]. The longest river on the Peninsula is the Tagus. Its total length is 1,038 kilometers [645 miles]. The Tagus originates in northeastern Spain. It flows into Portugal at the border. The Tagus empties into the Atlantic Ocean at Lisbon.

Tagus River

Tagus River

Tagus River

Tagus River

Tagus River

Tagus River