Carthage is a city in and the county seat of Hancock County, Illinois, United States. Its population was 2,490 as of the 2020 census. Carthage is best known for being the site of the 1844 death of Joseph Smith, who founded the Latter Day Saint movement.

U.S. Route 136 is an east-west U.S. highway that is a spur route of U.S. Route 36. It runs from Edison, Nebraska, at U.S. Route 6 and U.S. Route 34 to the Interstate 74/Interstate 465 interchange in Speedway, Indiana. This is a distance of 804 miles (1,294 km). Due to the removal of almost every numbered route in Indianapolis, US 136 never meets its parent, US 36; however, it does come within two miles of it at its interchange with I-465/I-74 at its eastern terminus.