The Morrill Anti-Bigamy Act was a federal enactment by Congress that was signed into law July 8, 1862, by President Lincoln. It was aimed mostly at the Mormon church who practiced polygamy. Polygamy was a source of tension between the Government and the Mormon church. The act banned polygamy in federal territories (which Utah was) and limited church and non-profit ownership in any territory to $50,000. The act targeted the Mormon practice of polygamy and church ownership of property.
In 1890 the Church published a manifesto banning plural marriages. All of this was occurring during the Civil War and Utah was a territory far away, so the law was almost impossible to enforce. Lincoln himself chose not to enforce it. It would seem that this issue would not be of importance to Midwestern citizens of small-town Leland, Illinois. However, the above petition from the National Archives tells a different story. Many women in town made it clear to early Leland Mormon settlers that polygamy would not be welcomed in Leland.
Woman signers were