Illinois State Maps

These maps show Illinois Counties, Cities, Federal Areas, Physiographic, and Ecoregions.




Illinois County Map

The Counties of Illinois and Their Name Origins

Illinois County Sizes Map

Illinois State County Sizes Map

Smallest County in Illinois

Putnam County: 170 sq miles

Largest County in Illinois

McLean County: 1,185 sq miles

Mean and Median Area of Counties in Illinois

Mean Area: 600 sq miles

Median Area: 517 sq miles

Illinois Major Cities Map

Major Cities of Illinois State and Their Locations

In Illinois, major cities are typically located near key transportation routes such as rivers, railroads, and highways. Below are examples of these cities:

1. River Ports

Chicago: Located on the southwestern shores of Lake Michigan, Chicago has historically been a major hub for transportation and trade. The city's port connects the Great Lakes to the Mississippi River system, making it a key city for shipping and commerce in the Midwest.

Peoria: Situated along the Illinois River, Peoria developed as a key industrial and agricultural hub due to its river access. It remains an important center for manufacturing and is also known for its contributions to the agricultural machinery industry.

East St. Louis: Located on the eastern side of the Mississippi River, across from St. Louis, Missouri, East St. Louis historically served as a key river port and industrial city. Its location on the Mississippi River facilitated trade and transportation in the region.

Quincy: Another river city on the banks of the Mississippi River, Quincy has long been an important agricultural trading hub. Its access to river transportation made it a center for shipping agricultural products like grain and livestock.

2. Rail and Road Hubs

Springfield: The state capital, located in central Illinois, grew around its strategic position at the crossroads of major railroads. Today, Springfield is known not only for its political significance but also for its rich historical ties to Abraham Lincoln.

Rockford: Located near the Wisconsin border, Rockford became a key manufacturing center due to its proximity to rail and road networks. The city continues to play a significant role in Illinois' industrial sector, particularly in aerospace and manufacturing.

Joliet: Situated southwest of Chicago, Joliet is a major transportation hub, with key railroads, highways, and the Illinois and Michigan Canal all converging in the area. The city is also known for its historical architecture and cultural contributions to the region.

Decatur: Located in central Illinois, Decatur grew as an agricultural and manufacturing center, thanks to its strategic position along the rail lines and highways. It remains a hub for grain processing and industrial activity.

3. Historic and Industrial Centers

Aurora: As one of the largest cities in Illinois, Aurora grew rapidly during the 19th century due to its role in the development of the railroad industry. Today, Aurora continues to be an important suburban and industrial center, known for its historic downtown and architecture.

Elgin: Located along the Fox River, Elgin developed as an industrial center in the late 19th and early 20th centuries, particularly known for its watch manufacturing. It has since grown into a significant city in the Chicago metropolitan area, with a mix of suburban development and industry.

Champaign-Urbana: This twin city area in central Illinois is home to the University of Illinois, making it a significant educational and research hub. The city's economy is driven by education, technology, and research industries, and it is an important center for innovation in the state.

Bloomington-Normal: These twin cities in central Illinois are known for their strong agricultural and insurance sectors. Bloomington is home to State Farm Insurance, while Normal hosts Illinois State University, contributing to a vibrant educational and business environment.



Illinois State Green Shaded Relief Map

Illinois State Shaded Relief Map

Topographic Tour of Illinois

Illinois is known for its relatively flat terrain, but the state offers various unique topographical features worth exploring.

1. Central Lowlands

The central part of Illinois is dominated by flat plains and farmland. This region was shaped by glacial activity during the Ice Ages, leaving behind fertile soils. It is ideal for agriculture, especially corn and soybeans.

2. Eastern Lake Section

Along the eastern side of Illinois, the shores of Lake Michigan provide a unique coastal environment, home to major cities like Chicago and large harbors that play critical roles in commerce and trade.

3. Mississippi Alluvial Plain

Southern Illinois includes the floodplains of the Mississippi River. This area features wetlands, oxbow lakes, and rich, alluvial soils that support a wide range of wildlife and agricultural activities.

4. Driftless Area

In the northwest, Illinois has a section of the Wisconsin Driftless Area, known for its rugged hills, deep valleys, and unique ecosystems, which stand in stark contrast to the surrounding flat terrain.

Illinois Physiographic Map

Physiographic Regions of Illinois

CENTRAL LOWLAND, DISSECTED TILL PLAINS

The Dissected Till Plains are primarily composed of rolling hills, carved out by rivers and streams. This region is mostly agricultural, with soils formed from glacial till, making it highly fertile.

CENTRAL LOWLAND, EASTERN LAKE

This region includes the area surrounding Lake Michigan, where the geography supports large cities, industrial areas, and ports.

CENTRAL LOWLAND, TILL PLAINS

The flat Till Plains region, covering central Illinois, is known for its highly productive agricultural lands, with a significant portion used for corn and soybean farming.

CENTRAL LOWLAND, WISCONSIN DRIFTLESS

This unique region was untouched by glaciers, resulting in rugged hills and valleys. It is located in the far northwestern part of the state.

COASTAL PLAIN, EAST GULF COASTAL PLAIN

The southern tip of Illinois includes part of the East Gulf Coastal Plain, where the terrain is flatter and more suited to agriculture and wetland ecosystems.

COASTAL PLAIN, MISSISSIPPI ALLUVIAL PLAIN

This region, along the western side of Illinois, is characterized by low-lying floodplains along the Mississippi River.

INTERIOR LOW PLATEAUS, HIGHLAND RIM

This region in southern Illinois is characterized by low plateaus and ridges, interspersed with rolling hills and agricultural land.

OZARK PLATEAUS, SPRINGFIELD-SALEM PLATEAUS

The Ozark Plateaus include the Springfield-Salem Plateaus, a region of southern Illinois with rugged terrain, scenic landscapes, and rich biodiversity.

Illinois Federal Lands Map

Notable Federal Lands: Some of the Largest and Most Fascinating Destinations in Illinois

1. Shawnee National Forest

Shawnee National Forest, located in southern Illinois, is known for its scenic vistas, rugged terrain, and diverse ecosystems. The forest offers numerous recreational opportunities, including hiking, camping, and rock climbing. Major sites include the Garden of the Gods, Rim Rock, and Bell Smith Springs. The forest is also home to a rich variety of flora and fauna, making it a prime location for nature enthusiasts.

2. Midewin National Tallgrass Prairie

Midewin National Tallgrass Prairie, located southwest of Chicago, is a protected area focused on the restoration of native prairie ecosystems. Visitors can explore miles of hiking and biking trails through the grasslands. The prairie also offers opportunities for bird watching, with many species of migratory birds, and bison have been reintroduced to the area to help restore the ecosystem.

3. Cache River State Natural Area

While not a federal land, Cache River State Natural Area in southern Illinois is one of the state's most unique ecosystems, featuring ancient cypress swamps and a diverse array of plant and animal species. It offers excellent opportunities for kayaking, wildlife viewing, and nature photography. The area is home to several rare and endangered species, as well as some of the oldest trees in Illinois.

4. Upper Mississippi River National Wildlife and Fish Refuge

Spanning four states, including Illinois, the Upper Mississippi River National Wildlife and Fish Refuge is a large and ecologically significant area along the Mississippi River. In Illinois, it offers opportunities for fishing, boating, and bird watching, particularly during migratory seasons. The refuge protects vital wetlands and floodplain ecosystems that are crucial for fish and wildlife.

5. Crab Orchard National Wildlife Refuge

Located near Carbondale in southern Illinois, Crab Orchard National Wildlife Refuge is known for its mix of recreational opportunities and conservation areas. Visitors can enjoy fishing, boating, and camping around Crab Orchard Lake, while the refuge’s diverse ecosystems support a wide range of wildlife, including bald eagles, white-tailed deer, and waterfowl.

6. Illinois and Michigan Canal National Heritage Corridor

The Illinois and Michigan Canal National Heritage Corridor stretches from Chicago to LaSalle and celebrates the history of the canal that connected the Great Lakes to the Mississippi River. While much of the canal is no longer in use, the corridor preserves its historical significance, offering hiking, biking, and interpretive tours along the former towpaths.

Illinois Ecoregions Map

Ecoregions of Illinois

1. Central Dissected Till Plains Section

This ecoregion is characterized by rolling hills formed from glacial till, with agriculture being the dominant land use. It is home to a variety of native plants and wildlife, including species adapted to the patchy woodlands and prairies that once dominated the landscape. Today, most of the land is used for corn and soybean production.

2. Central Loess Plains Section

The Loess Plains are composed of wind-deposited silt (loess), which creates highly fertile soils ideal for farming, particularly in central Illinois. The region supports extensive agricultural activities, especially row crops such as corn and soybeans. Remnants of prairie and savanna ecosystems can still be found in some protected areas.

3. Central Till Plains, Beech-Maple Section

This ecoregion features forests dominated by beech and maple trees, with agricultural lands interspersed throughout. The relatively moist climate of this region supports mixed hardwood forests, although much of the area has been cleared for agriculture. Some forested areas still provide important habitats for wildlife and help preserve biodiversity.

4. Central Till Plains, Oak-Hickory Section

The Oak-Hickory section is known for its forests dominated by oak and hickory trees, which are scattered across an agricultural landscape. These forests provide important wildlife habitats, and many state parks and conservation areas are located within this region to protect the remaining woodlands and promote biodiversity.

5. Interior Low Plateau, Shawnee Hills Section

Located in southern Illinois, the Shawnee Hills section is characterized by rugged terrain, bluffs, and steep ridges. It is part of the larger Interior Low Plateau, and the mixed deciduous forests here contain a variety of oak, hickory, and maple species. The region is home to the Shawnee National Forest, a major conservation area offering recreation and biodiversity.

6. Mississippi Alluvial Basin Section

This section lies along the western edge of Illinois, bordering the Mississippi River. It features wetland ecosystems, floodplains, and bottomland forests, which are home to numerous species of migratory birds, waterfowl, and other wildlife. This region plays a critical role in flood control and habitat preservation, particularly in conservation areas like the Upper Mississippi River National Wildlife and Fish Refuge.

7. Southern Till Plains Section

This ecoregion, found in central and southern Illinois, is characterized by flat to gently rolling plains created by glacial till deposits. It is primarily an agricultural region, with large areas dedicated to corn, soybean, and wheat farming. Despite its agricultural focus, there are pockets of prairie, wetlands, and woodlands that provide habitat for native species.

8. Ozark Plateau Section

Located in the southwestern part of Illinois, the Ozark Plateau features rugged topography with steep hills, ridges, and forests. This region is an extension of the larger Ozark Plateau found in Missouri and Arkansas. The area is known for its limestone and sandstone bluffs, as well as caves and springs that support diverse ecosystems.

9. Illinois River Bluffs Section

This section, which runs along the Illinois River, is known for its steep bluffs and deep ravines. The river has carved out this unique landscape over millennia. The area supports forests, prairies, and wetlands, and is a critical migration corridor for birds and other wildlife. Several conservation efforts aim to protect this ecologically important region.

10.Upper Gulf Coastal Plain Section

This section is located in the south part of the state and is known for its distinctive geological, ecological, and biological features that set it apart from other regions in Illinois. This area has bottomland forests, oak-hickory forests, wetlands, and prairies. Major water systems such as the Cache River and Ohio River contribute to the region’s rich wetland ecosystems, supporting a diverse range of aquatic and bird species.