The Ninth Wisconsin Legislature convened from January 9, 1856, to March 31, 1856, in regular session, and re-convened from September 3, 1856, to October 14, 1856.

The start of the session saw the dispute over the 1855 Wisconsin gubernatorial election, in which the Democratic incumbent governor, William A. Barstow, was forced to resign from office three months into this term after the Wisconsin Supreme Court threw out a number of apparently fraudulent votes.

Before he left office however, Barstow was involved in an extensive railroad bribery scandal, which ultimately also implicated his Republican challenger, Coles Bashford, and a huge portion of the members of the 9th Wisconsin Legislature.

[1][2] Senators representing even-numbered districts were newly elected for this session and were serving the first year of a two-year term.

At that time, the lieutenant governor, Democrat Arthur MacArthur Sr., of Milwaukee County, then ascended to become governor until the Wisconsin Supreme Court ruled that Republican Coles Bashford, of Winnebago County, had actually won the 1855 election and was entitled to the seat.