City comparison
Chicago, IL is about 275 miles (425 km) from O'Fallon, MO in a straight line. By road, the drive is roughly 325 miles, or about 5 h 30 min behind the wheel at highway speeds.
Driving distance is a rough estimate (great-circle × 1.25); driving time assumes a 60 mph blended average. Real trips run 10–20% longer with stops.
A direct flight from Chicago, IL to O'Fallon, MO takes about 32 min, covering roughly 275 miles in a straight line. Connecting itineraries with a layover typically add 1–3 hours.
Block-to-block estimate at ~500 mph cruise, including taxi, climb, and descent — what an airline would publish, not pure airborne time.
Chicago has a population of 2,721,914, vs 91,825 in O'Fallon — about 29.6× larger by population. By land area, Chicago covers about 230 sq mi vs 31 sq mi for O'Fallon.
Population from US Census ACS. Land area from the Census Gazetteer (city proper, excluding inland water).
Cost indices by category, with the US city average (100) marked.
Index: 100 = US city average. Lower is more affordable.
Side-by-side costs, salaries, and sub-category indices.
| Metric | Chicago | O'Fallon | Difference |
|---|---|---|---|
| Median rent | $1,314/mo | $1,311/mo | 0.2% higher in Chicago |
| Median home value | $304,500 | $283,600 | 7.4% higher in Chicago |
| Median household income | $71,673 | $104,863 | 46.3% higher in O'Fallon |
| Groceries index | 106.4 | 99.7 | 6.7% higher in Chicago |
| Utilities index | 84.4 | 71.9 | 17.4% higher in Chicago |
| Transportation index | 100.3 | 98.5 | 1.9% higher in Chicago |
| Healthcare index | 100.2 | 98.7 | 1.6% higher in Chicago |
How much you'd need to earn in the other city to keep the same standard of living.
If you earn $100,000 in Chicago, you'd need $85,169 in O'Fallon to maintain your standard of living.
Climate, safety, and demographics side by side.
O'Fallon, MO is about 14.8% cheaper overall than Chicago, IL, based on our cost-of-living index. Housing costs are roughly 37% higher in Chicago than in O'Fallon. If you earn $80,000 in Chicago, you'd need about $68,135 in O'Fallon to keep the same standard of living.