Seymour was founded in 1868 and named after Governor Horatio Seymour of New York. Seymour is said to have once been called Squeedunk, which means "little settlement" or "village".
William and John Ausbourne were the first settlers in Seymour. They had traveled from western Outagamie County on the Wolf River during the summer of 1857, making their way to the mouth of the Shioc River and moving to a spot where the Black Creek flows into the Shioc. After finding no more roads to follow, the Ausbournes settled in the present location of Seymour, which was occupied by Native Americans at the time. There they built a log house, the only residence in Seymour for two years. Their closest neighbors lived in Osborn.
Over the years more settlers came to Seymour. Willis and Dan Mungers arrived in 1864. They built a house on what is now Main Street and their daughter Sally lived in a frame house on what is now South Main Street. Erastus C. Buttles came during the spring and established a farm in the western part of the county. Leaonard and Avery Carter arrived in Seymour in 1876, along with Charles Eichler, the first German settler in the area.
During the early 1880s, construction of the Green Bay and Lake Pepin Railroad was completed. In 1883 a station was built in Seymour, and soon Seymour was recognized as the smallest incorporated city in the nation.
When the settlers had built their houses, they turned to education, electing a school superintendent and an establishing a school tax.. The schoolhouse was a simple one-room building with no floor and a shake roof.
Between 1887 and 1889 George E. Mendell published the first newspaper, The Aurora, which lasted only three years. On July 8, 1886 the Seymour Press made its first appearance, and was published by the Van Vuren family for over 80 years. It was then sold to the Shellman Publishing Company of Oconto Falls, and is still published today.
The Seymour Community Historical Society was officially incorporated on October 11, 1975. A dedicated group of local historians led by Tom Duffey, Rita Gosse, and Bill Collar established the society with the assistance of the State Historical Society of Wisconsin. Since its inception, SCHS members have been active in collecting and preserving records and physical objects relating to the city of Seymour and the surrounding area.
On July 21, 2012 the new Seymour Community Museum opened. The new facility built for $1.2 Million dollars which was entirely funded by private donors.