Named in passing, not visited
The Corps did not council with the Iowa. Clark still writes them into June 1804 as a nation at war on the lower Missouri, under the name Aiaouez / Aiauway.
On 17 June 1804, at a crossing used by war parties against the Osage, he listed the nations who used it:
the Saukees, Aiaouez, & Souix
On 28 June, describing the Kansa as poorly supplied with firearms, he wrote that they “become easily conquered by the Aiauway & Saukees who are better furnished with those materials of war.”
Those two sentences are the Iowa record in this corpus. Later Ordway footnotes that mention “Iowa” are modern place-names (the state line, Council Bluffs, Iowa), not the nation. An earlier draft of this page reported zero entries because the Iowa tag was empty, not because Clark is silent.