The counts were deposed during the French Revolutionary Wars, and Immenstadt briefly became Austrian before joining Bavaria in 1805. After major town fires in 1805 and 1844, Immenstadt entered the modern era in the 1850s, when the railroad arrived and the town's first factory opened shortly afterward. Immenstadt became a garrison town in the First World War and was bombed once in the Second World War, which cost six lives and destroyed several buildings along the railroad tracks. The town has enjoyed quiet prosperity since, with the exception of a flooding of parts of the municipal territory in 1999. The administrative reform of 1972 resulted in the incorporation of six nearby villages.