Alto Pass is a village in Union County, Illinois, United States. The population was 342 at the 2020 census, a decrease from 391 in 2010. The Bald Knob Cross and Bald Knob Wilderness are nearby. Alto Pass lies roughly 5.1 miles to the northwest of downtown Cobden, Illinois. Illinois Route 127 runs just west of the village's downtown area.

Union County is a county located in the U.S. state of Illinois. According to the 2020 United States Census, it had a population of 17,244. Its county seat is Jonesboro. It is located in the southern portion of Illinois known locally as "Little Egypt".