Iowa's 3rd congressional district is a congressional district in the U.S. state of Iowa that covers its southwestern quadrant, which roughly consists of an area stretching from Des Moines to the borders with Missouri.

David Bremner Henderson, a ten-term Republican congressman from Dubuque, Iowa, was the speaker of the United States House of Representatives from 1899 to 1903. He was the first congressman from west of the Mississippi River, the last Civil War veteran, the second foreign-born person, and the only Iowan to serve as Speaker.