Iowa's Southern Boundary

How did Iowa come to have the shape it has today? Determining the location of Iowa’s borders was an essential step in our path to statehood.

A Line Is Drawn

The western boundary of Iowa was disputed because the words "the middle of the main channel of the Missouri River" did not point to a real place that was always easy to find. The same was true for what would become the southern boundary of Iowa. When Missouri—the state that is directly south of Iowa—wrote its constitution, it described the state's northern boundary as "the rapids of the river Des Moines." This description was used in their state constitution when Missouri voters accepted statehood in 1821. Later, trouble started because state and federal governments could not agree on where "the rapids of the river Des Moines" really were.

In 1816, before Missouri or Iowa became states, Colonel John C. Sullivan surveyed and marked what would soon become the northern boundary of Missouri. His survey was supposed to be a "parallel of [the] latitude which passes through the rapids of the river Des Moines," but he made a mistake. He did not adjust his compass as he moved eastward from the Missouri River. This caused his boundary line to angle upward until it was four miles further north on the east (Mississippi River) side than on the west (Missouri River) side. Few people knew this though, and it would only become important when many people began to settle the area.

Where Missouri Ends and Iowa Begins

As settlers quickly moved into the Iowa country after 1833, they started farms and towns. As these grew, the settlers wanted to know just where the northern Missouri boundary line was. One of the reasons they wanted to know was because of slavery. Missouri was a slave state and many people in the area did not want to live where laws allowed one man to own another man.

Missouri officials also wanted to be sure just where the boundary was. They believed that the Des Moines rapids were much farther north than the Sullivan line. Therefore, Missouri officials sent Joseph C. Brown to re-survey the boundary line in 1837. He was supposed to begin at "the rapids of the river Des Moines" and then mark his line as he moved westward toward the Missouri River. He found a place on the Des Moines River near Keosauqua which he thought was the spot described by the words. This place, Great Bend, was 63 miles upstream from the mouth of the Des Moines River where it flows into the Mississippi River. He marked his line from Great Bend to a parallel spot near the Missouri River. Missouri then claimed Brown's line as its northern boundary.

The difference between the two lines was about 2,600 acres. Most of the settlers living on the disputed strip of land thought they had settled in the Iowa country. Much of it was rich farm land, which officials from both Missouri and Iowa Territory claimed as part of their jurisdiction. But in 1839 Missouri sheriffs tried to collect taxes from settlers in the disputed strip. Iowa Territorial Governor Robert Lucas warned Missouri Governor Lilburn Boggs that the Missouri sheriffs would not be permitted to do this. Governor Boggs warned Governor Lucas that the Missouri militia might be brought out to make sure the taxes were collected.

The "Honey War"

When another Missouri sheriff tried to collect taxes, an Iowa sheriff arrested him. Of course this angered Missouri officials, and in the icy cold December of 1839 the Missouri militia was ordered to the border area. In response, Governor Lucas called for Iowa volunteers to meet at the border town of Farmington. As troops gathered from both sides, people in the area began to think that there might really be war between Iowa and Missouri.

William Willson reported that while on business in Missouri he and his crew had been stopped and searched by soldiers. The soldiers were looking for ammunition. Other reports told of Iowa citizens who had been held in Missouri as spies.

Before things had gotten to this state, Albert Miller Lea had been sent by President Martin van Buren to decide which line was the correct boundary between Iowa Territory and Missouri. Lea wrote that it was general knowledge that "the rapids of the river Des Moines" were in the Mississippi River, not the Des Moines River. He suggested that the Sullivan line was not an accurate one, yet it had often been used in legal papers as the northern boundary of Missouri. But when the war was about to start, the federal government had not made a decision. Just when it looked as though the first shot would be fired, the Missouri troops were dismissed, and Missouri's jurisdiction was withdrawn back to the Sullivan line. The Iowa troops gladly went home. The "war" was over, and no one had been killed. These events were later called the "Honey War" because early in the conflict someone had destroyed some valuable honey-filled trees which were growing in the disputed strip. A poem was later written about the war and set to the tune of Yankee Doodle. It made fun of the two governors for their part in creating the needless conflict.

A Line Is Drawn Again

Even though the "Honey War" had ended, the boundary issue was not settled right away. The United States Supreme Court finally decided the boundary issue in 1851. The court decided that the Sullivan line was the best boundary because it had been used so often in treaties. The court also ordered that the Sullivan line be re-surveyed and re-marked, correctly this time. Big cast iron monuments, each weighing about 1,600 pounds, were placed at the east and west ends of the line. Smaller cast iron posts were placed every tenth mile, and wooden posts were placed every mile along the boundary line.

One more survey was done in 1896, again at the request of the United States Supreme Court. A few of the wooden mile markers were replaced at that time with stone monuments. Some of these cast iron and stone markers can still be found today along Iowa's southern boundary.


  • Jeffrey Madsen, “The Southern Boundary,” The Goldfinch 4, no. 3 (February 1983): 7-8.