At Wisconsin statehood, the Senate had only 19 districts. The 1st District consisted of Brown, Calumet, Manitowoc and Sheboygan counties.
For the 1853 session, the Senate was expanded to 25 members, and the 1st District lost Brown County.
For the 1857 session, the Senate was again expanded, to 30 members, and the District was reduced to Sheboygan County alone (the rest of the district became the new 19th District).
As of 1862, the Senate expanded to 33 seats, a size it would retain well into the 21st century; the 1st District remained unchanged.