In the Illinois Supreme Court, Lincoln & Herndon and Joshua P. Cooper represent the plaintiffs in the appeal case of Stark et al. v. Kester, a suit involving the partition of some land. The attorneys file a writ of error, and Herndon asks the Court "for leave to file additional errors herein." The Court grants the request. Writ of Error , filed 11 January 1858, Stark et al. v. Kester, Illinois Supreme Court, case file 2598; Order, 11 January 1858, Stark et al. v. Kester, Illinois Supreme Court, Journal Record SC 2nd GD, 117, both in Illinois State Archives, Springfield, IL.

In the U.S. Circuit Court, Lincoln & Herndon file a demurrer for plaintiff James Emmitt in the case of Emmitt v. Barret. Emmitt is suing James A. Barret for $8,000 in damages in a dispute concerning a promissory note. Collett v. Armour, in which Lincoln & Herndon appear for defendant, is settled by agreement. Demurrer, filed 11 January 1858, Emmitt v. Barret; Declaration, filed 2 January 1858, Emmitt v. Barret, both in Record Group 21, case file 279, National Archives and Records Administration, Great Lakes Region, Chicago, IL.