On July 21st, 1985, the Flint Hill Fire became the largest fire in fifty years in the Black Hills according to the Lead Daily Call. The Flint Hill Fire burned nearly 22,000 acres east of Edgemont. The Seven Sisters fire, which smoldered near Angostora Reservoir, burned 9,300 acres earlier during the week but was stopped before it reached Hot Springs. The estimated cost to contain the Flint Hill Fire was $1.5 million in 1985 dollars.
The previous record was held by the McVey Fire which destroyed 21,857 acres near Hill City in 1939 and was not surpassed until the 2000 by the Jasper Fire.
For more on historical fires, included a list of the largest and most damaging, see this 2016 report by KOTA. For further information on Wildfire Preparedness, see out Black Hills Knowledge Network Resource page.