Tam: கூடலூர் gūṭalūr
‘Valley Town’ Town/Taluk, Tamil Nadu
From Bad: goḍalu, ‘dale between two hills’, ‘basin’, ‘valley’; and Bad/Tam: ūru village, town.
The location matches the derivation perfectly.
Gudalur is a tea plantation region sitting at the foot of the Nilgiris and bordering two other states, Kerala and Karantaka; and the Mudumalai Tiger Reserve, en route from Mysore.
For related place names see Indian Place names and Tamil Nadu place names.

Places to visit sign (Gudalur) ganuullu