Tanjay City was created by virtue of Republic Act 9026 otherwise known as An Act Converting the Municipality of Tanjay, Province of Negros Oriental into a component City to be known as the City of Tanjay. The Act was approved and signed into law by President Gloria Macapagal-Arroyo on March 5, 2001.

Having a total population of 70,196 based on the 2000 census, the City has total land area of 27,605 hectares, of which .90% is classifed as residential while 76% is devoted to agricultural uses.

Likewise known as the City of Festivals, the City celebrates different festivities on a monthly basis whole year round, as one of the attractions it promotes in relation to its tourism related activities.

Currently classified as 5th class, Tanjay City is awaiting the approval for its reclassification as a 2nd class city.
The City of Tanjay was divided into 24 policical barangay that was headed by their respective baangay captain, these barangay includes:

Azagra
Bahi-an
Luca
Manipis
Novallas
Obogon
Pal-ew
Poblacion I (Barangay 1)
Poblacion II (Barangay 2)
Poblacion III (Barangay 3)
Poblacion IV (Barangay 4)
Poblacion V (Barangay 5)
Poblacion VI (Barangay 6)
Poblacion VII (Barangay 7)
Poblacion VIII (Barangay 8 )
Poblacion IX (Barangay 9)
Polo
San Isidro
San Jose
San Miguel
Santa Cruz Nuevo
Santa Cruz Viejo
Santo Niño
Tugas