Pietro Marchelli (9 March 1806 - 29 October 1874) was an Italian architect active mainly around Reggio-Emilia.
Pietro was born in Reggio Emilia in 1806. His father, Domenico was also an architect.[1] He initially studied mathematics at the University of Modena, graduating in 1830. He dedicated himself to be an engineer and architect in his native Reggio, where his father and uncle had been court architects. Among his major works are the refurbishment of the Palazzo Ducale, The design of the Foro Boario, and design of the Synagogue of Reggio Emilia. He became professor of architecture at the School of Fine Arts of Reggio. He was made Cavaliere dell'Ordine del Cristo from Portugal.