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
Building a van for Illinois
A van is close to the ideal Illinois vehicle. The byways are paved, the distances between towns are short, and the federal camping is developed: 24 drive-in sites statewide, almost all of them at Corps of Engineers lakes with tables, water and a dump station somewhere on the reservoir. Both trailer camps and vehicle camps on state ground are capped at 40 feet overall, which no van approaches.
Ask your builder about damp rather than deep cold, and about ground clearance rather than lockers. Illinois winters are long and wet rather than severe, and the thing that will actually stop a van here is a soft gravel forest road after a spring storm.
A conversion is a small house on a moving, flexing, weight-limited platform. The builder insulates and lines the shell, installs the electrical system, plumbing, heat and ventilation, builds the bed, galley and storage, and cuts the holes for windows, fans and vents that you do not want to get wrong.
Some shops build complete vans to a set floor plan. Others build to order, and a few will take on partial work such as electrical only.
A typical conversion includes
01Insulation, wall and ceiling panels, and flooring
02House battery, alternator charging, solar, inverter and shore power
03Roof fan, heater, and sometimes air conditioning
04Fresh and gray water, a sink, and sometimes a shower and water heater
05Bed, galley, seating and storage
06Windows, racks, ladders, awnings and exterior lighting
How to choose a van builder
Floor plans are easy to fall for. The questions underneath them matter more.
01Decide between a shop's standard layout and a custom build. Standard layouts are faster, and the shop has already solved their problems.
02Ask what the finished van weighs with water and gear. Sprinters are sold in several gross weight ratings, and a heavy build on the lightest chassis leaves little margin.
03Ask how the electrical system is protected and documented, and whether the components can be serviced on the road.
04Ask how cabinetry is fastened to the van. Furniture that is only screwed to thin wall panels works loose on rough roads.
05Ask how added seats and seat belts are engineered and anchored if anyone rides behind the front row.
06Get the scope, price, payment schedule and delivery date in writing.
What to have ready before you ask for a quote
The van you order decides what can be built in it, so it helps to talk to a builder before you buy.
01Model year, 144 or 170 wheelbase, roof height, and two-wheel, all-wheel or four-wheel drive
02How many people sleep in it and how many ride in it
03The seasons and climates you travel in
04Whether you need to work from it
05What goes inside with you: bikes, boards, dogs
06A budget range and the date you want to be traveling
Questions people ask
Do I need to own the van before I contact a builder?
No. Many builders would rather talk first, because the wheelbase, roof height and drivetrain you order decide what can be built. Some shops can also source a van.
How long does a Sprinter conversion take?
A full custom build is usually measured in months, plus whatever wait the shop has before it can start. Standard layouts are quicker. Ask for both numbers.
Should I get the 144 or the 170 wheelbase?
The 144 is easier to park, turn and drive on tight roads. The 170 gives you room for a fixed bed and a real galley without compromise. Think about where you will actually drive it, then about how you want to live in it.
Can these builders work on a Ford Transit or Ram ProMaster?
Many do. If you are on another platform, say so in the form and we will look for shops with that experience.
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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