Duncan McArthur Funk (June 1, 1832 – December 17, 1911) was an American politician, banker, and rancher from Illinois.
Funk was president of the First National Bank of Bloomington and had financial interests in several others.
He co-owned the store until 1866, when he returned to tend to the family farm following the death of his father.
Funk received 2,400 acres (970 ha) of his father's lands, where he raised cattle and hogs.
In 1896, Funk was elected on the Republican ticket to the Illinois House of Representatives, where he served a two-year term.