The first Minnesota Legislature first convened on December 2, 1857. The 37 members of the Minnesota Senate and the 80 members of the Minnesota House of Representatives were elected during the General Election of October 13, 1857. Although the Constitution of the State of Minnesota, which had been adopted by the voters at the 1857 general election, was not ratified by the United States Senate until May 11, 1858, this was the first legislature of the State of Minnesota to convene in conformity with the state constitution.

The legislature met in a regular session from December 2, 1857 to August 12, 1858, with a recess between March 25, 1858 and June 2, 1858. There were no special sessions; however, the regular session continued for 254 days, which still ranks the longest duration of any Minnesota Legislature. Due to the protracted length of the 1857-58 session, it was determined that an 1858-59 meeting of the legislature was unnecessary, and the 2nd Minnesota Legislature did not convene until December 1859.

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