settlers, establishing a Presbyterian Church in the same area as the present-day church, and a school house directly across from it on the west side of Governor Beveridge Highway. It's also widely known that this church was a stop on the underground railroad. Later, in 1836, the post office for the settlement of Somonauk was moved to the intersection of Chicago Road and Somonauk Road and the name would be changed to "Somonauk Crossing". Another post office was established in 1850 on Somonauk Road at present-day Buck Lake, and was known as "Buck's Branch". In 1851, the CB&Q railroad finally made its way through the township, and in 1853, built a station along the line 5 miles south of the early settlement (now known as "Franks"), just north of the LaSalle/DeKalb County border. With that, the name "Somonauk" would make one final move to its current location, being in platted in 1855, and incorporated in 1865. "Somonauk Crossing" then became known as "Freeland Corners". The name of Buck's Branch would change to "Somonoc Depot" for a brief time before the post office was moved to the actual Somonauk railroad depot in December 1855. The closing of "Freeland Corners" post office was such a hardship to the farmers of Freeland Corners and Somonauk Crossing, that they petitioned the Post Office Department to establish another office in the location of Frank Richey's creamers, and that it be called Frank's Post Office. A post office was established in November 1891, once again located in the area of Chicago Road and Somonauk Creek, this time, on the west side of Rimsnider Road, just north of the creek. The post office was discontinued in April 1902, lasting a mere 11 years. Geography Somonauk is located at (41.6327194, -88.6865175). The village is situated along the boundary between DeKalb and LaSalle counties. In the 2000 census, 1,190 of Somonauk's 1,295 residents (91.9%) lived in DeKalb County and 105 (8.1%) lived in LaSalle County. According to the 2021 census gazetteer files, Somonauk has a total area of , of which (or 99.76%) is land and (or 0.24%) is water. Sannauk Forest Preserve serves as the unofficial boundary between Somonauk and Sandwich, which resides to the east. The forest preserve, owned and managed by DeKalb County, sits along Somonauk Creek, a tributary of the Fox River. During the housing bubble of the mid-2000s, a few new subdivisions were planned