The city of Treinta y Tres is located on the left bank of the Rio Olimar.
Formerly in this place you could ford the river and was the route from Montevideo to Rio Branco.
Named after the landing of the Treinta y Tres Orientals crusade thirty three Orientals, led by Juan Antonio Lavalleja, launched in 1825 from what is now Argentina to regain the independence of the Eastern Province, then under Portuguese rule.