The largest Australian bushfires in a populous region in recorded history take place in the state of Victoria.

Bushfires in Australia are a widespread and regular occurrence that have contributed significantly to shaping the nature of the continent over millions of years. Eastern Australia is one of the most fire-prone regions of the world, and its predominant eucalyptus forests have evolved to thrive on the phenomenon of bushfire. However, the fires can cause significant property damage and loss of both human and animal life. Bushfires have killed approximately 800 people in Australia since 1851, and billions of animals.

The Black Thursday bushfires were a devastating series of fires that swept the Port Phillip District in Australia, on 6 February 1851, burning up 5 million hectares, or about a quarter of the state's area. Twelve people died, along with one million sheep, thousands of cattle and countless native animals.

"The temperature became torrid, and on the morning of the 6th of February 1851, the air which blew down from the north resembled the breath of a furnace. A fierce wind arose, gathering strength and velocity from hour to hour, until about noon it blew with the violence of a tornado. By some inexplicable means it wrapped the whole country in a sheet of flame – fierce, awful, and irresistible."

Victoria, commonly abbreviated as Vic, is a state in southeastern Australia. It is the second-smallest state, with a land area of 227,444 km² (87,817 sq mi); the second-most-populated state, with a population of over 7 million; and the most densely populated state in Australia. Victoria's economy is the second-largest among Australian states and is highly diversified, with service sectors predominating.