Somonauk is a village in DeKalb and LaSalle Counties in the U.S. state of Illinois. The population was 1,786 at the 2020 Census, down from 1,893 at the 2010 Census. The DeKalb County portion of Somonauk is part of the Chicago-Naperville-Elgin, IL-IN-WI Metropolitan Statistical Area, while the small portion that lies in LaSalle County is part of the Ottawa, IL Micropolitan Statistical Area. Early history The name "Somonauk" is of Pottawatomie origin. The name is most likely derived from the phonetic phrase As-sim-in-eh-kon, which translates to "pawpaw grove", in reference to the vast groves of pawpaw trees that filled the area at that time. The Second Treaty of Prairie du Chien, signed by General John McNeil Jr., Colonel Pierre Menard, and Caleb Atwater for the United States on June 29, 1829, references four sections of land being reserved for Chief Awn-kote and his band of 171 villagers "at the village of Saw-meh-naug along the Fox and Illinois Rivers". The Saw-meh-naug, along with the other Pottawatomie of the Illinois River (known as the Prairie Group), as well as the Sauk and the Chippewa, had aided the U.S. in the Black Hawk War. After the war, as a thanks to the Pottawatomie, the U.S. Government signed a treaty allowing the Prairie Group tribes to continue to hunt on U.S. land, outside of their allocated reservations. However, due to "rumors of the Pottawatomie being restless and committing depredations in the northern part of the state spreading to central Illinois", and white residents of the state feeling uncomfortable, the Governor "gave the Prairie Group an ultimatum to leave Illinois". By the end of December 1833, the Pottawatomie had left Illinois, and the settlements of the Pottawatomie were free to be claimed by white settlers. A few months later, in the spring of 1834, the first white settler in DeKalb County had set up shop along a tributary to the Fox River, and the name Somonauk was moved from the area of present-day Ottawa, to where Chicago Road, Governor Beveridge Highway, and Somonauk Creek meet. This is the area known as present-day "Franks". The simple log cabin was used as a station house along the Chicago-Galena mail route between Aurora and Genoa, and would eventually become property of the Beveridge family. This cabin was the first post office in Somonauk Township, and the area both east and west of Somonauk Creek would eventually have 30