Аннотация:The article provides data on the geological, tectonical and seismological situation of the region. Results of archaeoseismological field studies of the ancient fortress and castle of Mugkala and Mugtepa in the Fergana Valley (Namangan region, Uzbekistan) are considered. On the archaeological sites, we revealed such characteristic destructions and damages as pitches, inclinations, shaking, sagging, and extend through cracks and inter-brick cracks in the city walls, confirming their seismogenic origin. Similar seismic deformations can be considered as an evidence of the high local intensity of seismic vibrations. It was noted that seismic shocks propagated along the sub-latitudinal axis. Both archaeological sites Mugtepa and Mugkala are located between the North Fergana Fault and the North Fergana flexural-breaks zone. The seismicity of the research area is associated with the development of the Kasansai group of young, Q4 quaternary anticlinal folds. А new residence on Mugtepa could be built by a new Kings of Fergana Valley in the end I c. BC and it was destroyed in I c. AD by a strong earthquake with local seismic intensity IL = VIII–IX (MSK-64 scale). The residence of the Turkic Kaganate could be built by new kings of Fergana Valley in a new location. Mugkala was also be destroyed by a strong earthquake with seismic intensity IL = VIII–IX (MSK-64 scale) at the end of the 8th century AD. This earthquake caused the different deformations described in the paper