The newer XBee ZB Pro is 3.2 km (~ 2 mile) for LOS. You would need to use higher gain antenna though. If your region allows the use of 900 MHz and 868 MHz band radios, go for that instead. 
The newer XBee ZB Pro is 3.2 km (~ 2 mile) for LOS. You would need to use higher gain antenna though. If your region allows the use of 900 MHz and 868 MHz band radios, go for that instead.