Missouri Geography: The Land

Geography and Landforms of Missouri

Missouri is bordered by Iowa on the north and by Arkansas and Tennessee on the south. Illinois, Kentucky and Tennessee border the state on the east, and Nebraska, Kansas and Oklahoma form the western border. The highest point in Missouri is Taum Sauk Mountain at 1772 feet.

Major rivers in the state include the Mississippi River, the Missouri River, the Current River and the Osage River.

Missouri is made up of these Physiographic Areas

Dissected Till Plains

The Dissected Till Plains occupy much of Iowa, eastern Nebraska, northwest Missouri, and small parts of northwest Illinois, southern Minnesota, and northeast Kansas. This area was glaciated, uplifted, and subsequently eroded into a flat-to-rolling terrain that slopes gently toward the Missouri and Mississippi River Valleys. Natural vegetation is a mosaic of tallgrass bluestem prairie and oak-hickory forest with oak savannahs characteristic of transition zones. Bottomland hardwoods grow in river valleys.

Mississippi Alluvial Valley

This area includes the floodplain of the Mississippi River that cuts into the Gulf Coastal Plain, extending north to and including the delta at the confluence of the Mississippi and Ohio Rivers and south toward the Gulf of Mexico. The Alluvial Valley includes most of eastern Louisiana, eastern Arkansas, northwest Mississippi, small portions of west Tennessee and Kentucky, the bootheel of Missouri, and the Cache River lowlands of Illinois. Nonforested marsh in southern portions of the floodplain is included in the Coastal Prairie physiographic area. Water shaped this land. The ridges and swales, levees, oxbows, and terraces of the Valley all resulted from meanderings and floods of the Mississippi River. Small changes in elevation determine how wet a site is, the plant community that grows there, and habitat conditions for birds.

Osage Plains

The Osage Plains, covering west-central Missouri, the southeastern third of Kansas, most of central Oklahoma, and extending into north-central Texas, is the southernmost of three tallgrass prairie physiographic areas. It grades into savannah and woodland to the east and south, and into shorter mixed-grass prairie to the west. The Osage Plains consist of three subregions. The Osage Plains proper occupy the northeast segment. Although sharply demarcated from the Ozark uplift, the Plains are nonetheless a transitional area across which the boundary between prairie and woodland has shifted over time. In the central portion of the physiographic area lies the second subregion, the Flint Hills. This large remnant core of native tallgrass prairie is a rocky rolling terrain that stretches from north to south across Kansas and extends into Oklahoma. To the west and south of these hills are the Blackland Prairies and Crosstimbers. This vegetatively complex region of intermixed prairie and scrubby cedar-mesquite woodland extends into north-central Texas. As in the rest of the Great Plains, fire, herbivory, topography, and drought maintained prairie and established the location of woodlands.

Ozarks and Ouachitas

The Ozarks and Ouachitas are two distinct mountain ranges separated from each other by the Arkansas River Valley. The Ozarks occupy most of southern Missouri and extend into northern Arkansas. They consist of three dissected plateaus covered with oak-dominated forest with glade and savannah inclusions. To the south, the Ouachitas are a ridge and valley system covering central Arkansas and extending into eastern Oklahoma. Here shortleaf pine is interspersed with deciduous forest. The physiographic area transforms into prairie to the north and west and drops off into the Mississippi Alluvial Valley to the east and the West Gulf Coastal Plain to the south. The Ozark/Ouachitas are similar in many respects to the Interior Low Plateaus that lie directly to the east of the Mississippi Valley.

Prairie Peninsula

The Prairie Peninsula stretches from northeastern Missouri, across much of Illinois and through the middle of Indiana into Ohio. It is a gently rolling glacial plain in the west, but becomes flatter to the east, where prairie and oak openings were embedded in beech-maple forest. Tallgrass prairie, savannah, and forest habitats were interspersed throughout the Prairie Peninsula, although the percentage of prairie declined from west to east. Savannah occurred in transition zones between grasslands and forest, although the extent of savannah varied temporally and spatially with climatic conditions and other ecological influences. Vegetation patterns were influenced primarily by fire, many of which in recent centuries apparently were set by Amerindians.

Missouri Landscape and Landforms:

Dissected Till Plains

The Dissected Till Plains are north of the Missouri River. This area is covered with rich soil that is particularly good for growing corn. This well-watered prairie is criss-crossed by many slow-moving rivers and streams.

The Dissected Till Plains were formed around 400,000 years ago by the Nebraskan glaciations. Glacial scouring left behind the rolling hills and rich, fertile soils found today in the region.

Osage Plains

The Osage Plains cover western Missouri. This area is mostly flat but there are some hills. The soil in this region is not as rich as in the Dissected Till Plains. Corn and other grain crops are grown in the Osage Plains region.

Ozark Plateau

The largest land area in Missouri, this area is also known for its large springs, lakes, and clear rivers. The Ozark Plateau is located in the southwestern corner of Missouri, and is great for gardens and strawberries. The St. Francois Mountains are in the southeast. This area is the highest and most rugged section of the state. Taum Sauk Mountain, the highest point in Missouri, is located in the St. Francois Mountains.

Mississippi Alluvial Plain

This land, once swampy, has been drained to form a rich farmland suitable for growing cotton, soybeans, and rice. The southern portion of Missouri that juts into Arkansas, is called the Boot Heel because of its shape.

The alluvial plain consists of both Pleistocene (Ice Age) and recent deposits of clay, silt, sand, and gravel that were laid down by the Mississippi River as it meandered across this broad floodplain.