Jo Daviess County. Our own 3DEP reading at the USGS point is 1,234 feet. The low point is 279 feet where the Ohio joins the Mississippi at Cairo, a Corps of Engineers figure in the USGS table
Against under 32 inches in the north. Snow runs the other way, 36 inches a year up north and under 10 in the far south
Where four-wheel drive actually earns its keep
Honestly, not often, and that is worth saying plainly. Most Illinois public land is reached on pavement or on maintained gravel, and the one place a genuinely capable vehicle would be useful is a trail system it is not allowed on. Four-wheel drive here buys you a wet boat ramp, a soft campground pull-through, a rutted forest road in March and the confidence to keep going when it rains.
That points a shop at recovery and at traction on greasy clay rather than at articulation and gearing. Good tires, a working transfer case, a winch mounted where you can use it from a road edge, and boards worth carrying will cover almost everything Illinois does to a vehicle.
A 4x4 shop is where parts become a working vehicle. Most sell and install the major brands, and the better ones will talk you out of parts you do not need. For overland use, ask them to think about reliability and weight rather than looks.
Typical work
01Differential gears and lockers
02Armor: bumpers, sliders and skid plates
03Winch and recovery point installation
04Lift, wheels and tires
05Lighting, compressors and wired accessories
How to choose a 4x4 shop
Ask about the unglamorous work.
01Ask what they drive and where. Shops that travel build differently from shops that only show.
02Ask about differential work specifically if you need gears or lockers. Setting up gears is a skill, and a bad setup is loud and short-lived.
03Ask how they wire accessories: fused, relayed, loomed and labeled, or tapped into whatever was nearby.
04Ask about weight. Every part they sell you is weight you carry forever.
What to have ready before you ask for a quote
Start from the problem, not the part.
01Year, model and drivetrain
02Tire size and any lift
03What you want the vehicle to do that it cannot do now
04What is already installed
05A budget range
Questions people ask
Do I need lockers?
For most dirt-road travel, no. Good tires at the right pressure and careful driving go a long way, and many modern 4x4s have capable traction control. A rear locker becomes worth it when you regularly cross terrain where a wheel leaves the ground.
Winch or no winch?
If you travel alone, a winch is the one recovery tool that does not need a second vehicle. It also needs a bumper that can carry it, a battery that can feed it, and practice. If you always travel with others, traction boards and a rope may be enough.
What should I do first?
Tires, then recovery points and basic recovery gear, then whatever your first few trips tell you is missing. Trips are cheaper than parts and much better at showing you what you need.
How high is Illinois?
From Cairo at 313 feet to Charles Mound at 1,235.
Altitude decides what your engine, your brakes and your lungs have to work with, and how late in the year the passes open.
02,000
Feet above sea level
Towns
ShelbyvilleShelby County seat at Lake Shelbyville, six federal campgrounds and two state parks on one reservoir, with Hidden Springs State Forest ten miles southeast.646 ft
JonesboroUnion County seat. Mississippi Bluffs Ranger District office, Trail of Tears State Forest five miles northwest, and the LaRue Pine Hills loop starts here.570 ft
OquawkaHenderson County seat on the Mississippi. Big River State Forest and its 60 miles of firebreaks are eight miles north on the Oquawka to Keithsburg road.553 ft
WilmingtonOn State Route 53, the old Route 66 alignment, two miles south of the Midewin National Tallgrass Prairie headquarters and welcome centre.543 ft
Forest CityMason County village that is the headquarters address for Sand Ridge State Forest, the largest state forest in Illinois and its main backcountry camping.494 ft
BentonFranklin County seat off I-57. Rend Lake and its five public campgrounds sit west of town, with the Corps office on Rend City Road.473 ft
CarlyleOn US 50 fifty miles east of St. Louis at the largest lake in the state, with the Corps visitor centre on the shore and camping all round it.460 ft
MurphysboroJackson County seat on Route 149. Johnson Creek Recreation Area on Kinkaid Lake, one of four Shawnee campgrounds rated for a 40-foot rig, is northwest.419 ft
CarbondaleLargest town in southern Illinois and the working base for the western Shawnee. Giant City State Park is near town and the Mississippi Bluffs district office is south at Jonesboro.416 ft
ViennaJohnson County seat on Route 45. Hidden Springs Ranger District office, one of the forest’s two districts and the office that issues its own motor vehicle use map.412 ft
Carrier MillsAddress of the Sahara Woods site office and the nearest town to the only state-run off-highway vehicle trails in Illinois.395 ft
HarrisburgSaline County seat on US 45. Shawnee National Forest supervisor’s office is on Highway 145 south of town, the Garden of the Gods road leaves Route 145 for Route 34, and the state OHV park is five miles west.394 ft
Cave-in-RockOhio River village at the state park with the 55-foot cave. The free Cave-In-Rock Ferry crosses to Kentucky here, supported jointly by both states.375 ft
ElizabethtownHardin County seat on the Ohio River Scenic Byway, between the Garden of the Gods road and the river, with Tower Rock’s free campground east on Route 146.361 ft
GolcondaPope County seat on the Ohio River Scenic Byway, on the eastern side of the Shawnee in the Hidden Springs district.354 ft
CairoThe southern tip of Illinois where the Ohio meets the Mississippi at 279 feet, the state low point, and where the Illinois stretch of the Ohio River Scenic Byway ends.313 ft
Passes, high roads and summits
Charles MoundThe highest point in Illinois, in Jo Daviess County in the far northwest corner. Our own 3DEP reading at the USGS point is 1,234 feet1,235 ft
Williams HillPope County, high ground in the Shawnee Hills on the eastern side of the national forest. The figure is our own reading of the elevation surface at its map point, because no agency publishes one1,062 ft
Bald KnobUnion County, in the hills behind the Mississippi bluffs on the western side of the national forest. The figure is our own reading of the elevation surface at its map point, because no agency publishes one1,028 ft
Pass, road and summit elevations are the figures published by the agency that manages them. Town elevations are the town’s or county’s own
figure where it publishes an exact one; the rest are from the U.S. Geological Survey (3D Elevation Program at the place’s official coordinates),
retrieved September 18, 2026. Every source is listed at the foot of the page.
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