While Lewis and Clark ventured up the Missouri River, Zebulin M. Pike led an expedition of twenty men up the Mississippi River to its source. Jefferson’s purchase of Louisiana from France in 1803 had doubled the size of the United States, so he quickly commissioned the two teams to complete an exploration of this huge wilderness, and they were asked to select sites for the building of forts along the prominent waterways. It should be noted that the terms "fort" and "trading post" were often synonymous, as these bases of white activity accomplished more than one purpose while attempting to control the Indians.

Pike’s log says that he left St. Louis on August 9, 1805 and camped just below the mouth of the Des Moines River on August 19. On August 20, he describes the difficulty his men faced in ascending the Des Moines Rapids. And on the night of August 21, he camped on a sandbar 6 miles above an Indian Village in the vicinity of what is now Oquawka, Illinois.

Nowhere in Pike’s journal do I find mention of exploring the Des Moines River, yet according to an article in Palimpsest, May 1955, Zebulin Pike is credited with giving the first detailed description of this tributary as far upstream as the present site of Des Moines. Most historians agree with this assessment.

A map of the Mississippi to its source drawn from Pike’s notes was published in 1811. Here is shown (inaccurately) the River des Moines running almost straight north from a Sac village located near the bottom of the Des Moines Rapids on the Mississippi above the present Keokuk dam.

Pike places a large horseshoe bend in the river about fifty miles upstream, and twenty miles above that, the Ayouwa Village appears on the right hand side of the river. It can be noted that all tributaries on the map are labeled as rivers instead of creeks. For example, at the beginning of the bend are two streams called "Two Rivers." Chequest Creek appears as Paul River, a stream within what is now Lacey-Keosauqua State Park is labeled "Bad Buffaloe River," and Holcolm Creek at Leando is shown as "Grand River."

Opposite the Iowa village on the left side, Pike places Ft. Gelaspy and just below the Grand River, also left of the river, he places one of two Ft. Crawfords. Thirty miles or so upstream is another Fort Crawford across from a Ft. St. Louis and further upstream is another point named Crawford. Likely, these were recommended sites and might not have materialized. This is the only reference I have found to the two forts (Gelaspy and Crawford) near or in what was later Van Buren County.

One of the most interesting notations on this old map is a dot within Van Buren’s horseshoe bend labeled "great" with an illegible word that looks like town or turn. The marking is different than those used to pinpoint Indian villages.

Pike’s personal log of the expedition makes no mention of ascending the Des Moines, yet the map clearly indicates that it was thoroughly explored at least 100 miles inland above its mouth. From the team of twenty explorers that left St. Louis on August 9, some of them must have split from the party to investigate the Des Moines, the largest tributary that the group would encounter. Just when and how they regrouped with the other explorers would make a worthwhile study in itself. These interesting early records leave many unanswered questions!