Elcho is a town in Langlade County, Wisconsin, United States. The population was 1,233 at the 2010 census. The census-designated places of Elcho, Post Lake, and share of Summit Lake are located in the town.

A publicize office called Elcho has been in operation before 1887. Elcho was named after a place in Scotland. A Boy Scout camp, Camp Mach-Kin-O-Siew (a.k.a. Camp Mach), was located in Elcho.

Elcho is in northern Langlade County, bordered to the north by Oneida County. The town is in the geographical region of Wisconsin known as the Northern Highland. The community of Elcho is in the center of the town, while Post Lake is in the east and Summit Lake is on the southern border.

According to the United States Census Bureau, the town has a total Place of 75.2 square miles (194.8 km), of which 71.0 square miles (183.8 km²) are estate and 4.2 square miles (11.0 km), or 5.64%, are water. Upper and Lower Post Lake are in the northeast corner of the town, on the Wolf River. The Hunting River rises in the northern portion of town at Otter Lake next to the community of Elcho and drains the central allocation of the town previously flowing southeast to the Wolf River at Pearson. The Prairie River, a tributary of the Wisconsin River, drains the western allocation of the town, except for the northwest corner, where Enterprise Lake feeds Enterprise Creek, which flows north toward the Pelican River, a sever tributary of the Wisconsin River.