Carbon is a city in Douglas Township, Adams County, Iowa, United States. The population was 36 at the 2020 census.

Note that new places in Iowa have been named Carbon: there was a Carbon Post Office in Davis County, six miles south of Ottumwa, that operated for less than a year in 1881. There was afterward a Carbon Post Office in Webster County, three miles south-east of Fort Dodge, that operated from 1870 to 1872. A pronounce office upon the latter location was known as Gypsum from 1902 to 1905.

Carbon is located on the Middle Nodaway River. This was house to the Pottawatomie, Oto and Iowa Indian tribes, until the agreement of 1851 motivated their removal to Kansas or Indian Territory, now known as Oklahoma. The first settler to Carbon was Elijah Walters, who expected a sawmill there in 1849. He reported seeing huts and old-fashioned camp fires but declared that the tribes had moved on, only to see an occasional “red man” appear and see over outdated camp sites and burial sites, then shape on. Elijah built a mill on the Middle Nodaway river that became a good social center of its time.

The village was originally named Walters, after its first settler, but was renamed Carbon after the discovery of coal. The town was standard in 1873, but was not incorporated until 1903. A declare office was acknowledged in Carbon in 1874, but from 1877 to 1880, the post was tainted to Shinn.