The Interior Plateau ecoregion extends from extreme southern Illinois, central southern Indiana and southeast Ohio, through both western Kentucky and western Tennessee and into northern Alabama, covering an area of over 74,600 square miles.

Elevations ranges from a high of 1,060 feet at Williams Hill in Illinois to a low of 325 feet along the Ohio River as it leaves the ecoregion in Illinois and Kentucky. However, most of this ecoregion lies at the elevation of between 500 feet and 850 feet.

From about 1800, approximately 50 percent of the landscape was cleared and most wetlands drained by Euro-Americans. Fires became more frequent during this period, as did erosion, since the hill slopes had been denuded of timber for fuel.

Today, the landscape is a patchwork of forest and agricultural lands, the former used for recreation, ecosystem maintenance, and wood-fiber production, the latter for grazing and row crops. Energy and mineral production have affected small portions of the landscape; coal, iron, lead, zinc, fluorite, limestone, sand, and gravel have been mined in the ecoregion, beginning in the mid-1800's. Oil and gas production began in the early 1900's.

The lay of the land is mostly rolling hills with occasional areas of swampy alluvial valleys. There are also deeply entrenched rivers and their tributaries, as well as extensive karst plains. There are a few large rivers which cross this ecoregion, including: the Cumberland, Kentucky, Licking, Ohio, and Tennessee Rivers.

This ecoregion was originally covered with forests, except in the areas of karst plains which had barren lands, prairies as well as oak savanna.

Much of the ecoregion is characterized by rolling limestone plains punctuated with regions of fairly rugged topography. Topographical relief of up to 250 feet is common in many areas

The elevations of the Interior Plateau are lower than the Appalachian ecoregions in the east.

As part of the Interior Plateau, located entirely within Kentucky, is a sub region referred to as the Inner Bluegrass region. This region is relatively flat, agriculturally fertile, but has been heavily used for agriculture as well as urban and industrial development which has seriously altered and degraded the area.

The geology of the rock types in this ecoregion is distinctly different from the coastal plain sediments and alluvial deposits of ecoregions to the west.

The geology of the surface is of two primary types: (1) On the northern edges of the ecoregion in Ohio, Indiana, and much of Illinois, glaciated till plains are the primary landscape; (2) In the south, much of the geology in this ecoregion is penetrated by unglaciated limestone.

Mississippian to Ordovician-age limestone, chert, sandstone, siltstone and shale compose the landforms of open hills, irregular plains, and tablelands.

The natural vegetation is primarily oak-hickory forest, with some areas of bluestem prairie and cedar glades.

Over 150 bird species nest in the Interior Plateaus ecoregion and the primary game animals and furbearers of the region are the white-tailed deer, gray fox, red fox, raccoon, opossum, striped skunks, mink, muskrat, eastern cottontail, fox squirrel, and gray squirrel.

The paddlefish and sturgeon have been greatly impeded from their migration in these waters by locks, dams, and impoundments along the Ohio River and its major tributaries, which hinder populations and habitat. Other fauna in these waters are common throughout the State.

Prehistoric Native American activities seem to have had little effect on the Interior Plateau.

Meriwether Lewis Campground

Natchez Trace Parkway

Natchez Trace Trail

Natchez Trace Parkway