Five (Pancha) places (Kshetra), lying on the river Kaveri, where Vishnu is worshiped as Ranganatha. Ranga is the stage, Ranganatha is the Lord of the Stage. The stage is the world, the cosmos.
Adi Ranga, the primordial Ranga, is Srirangapatna.
The others are the Divya Desham Srirangam, Tiruppernagar, Tiruindhalur, Tirukudanthai.