LaSalle County, IL Elevation & Topographic Map
Elevation
920 ft 280 m780 ft 240 m710 ft 220 m580 ft 175 m440 ft 135 m370 ft 110 m
Zoom in for contour lines
USGS 3DEP · U.S. Census Bureau
How to use this mapviews, tools and data
- Elevation
- Ground colored by height from green (lowest) to white (highest), with contour lines every 40–500 ft (USGS data).
- Satellite
- A 2016 satellite photo at 33 ft (10 m) detail; contours off.
- 3D
- Tilt and turn the terrain; hills are raised 1.5×, or set ×1 for true height.
- Click or tap anywhere
- The exact elevation of that spot in ft and m.
- Measure
- Pick two points for the climb, descent and grade along a straight line.
- County area
- Fades everything outside the official county boundary (US Census).
Elevation Data
LaSalle County averages about 660 ft (200 m) above sea level across all its land. Its ground runs from 370 ft near the middle to 920 ft on the northwest side.
Average elevation
660 ft 200 m
all land inside the county
Highest
920 ft 280 m
on the northwest side
Lowest
370 ft 110 m
near the middle
LaSalle County spans about 550 ft of height, so no single spot tells the whole story. The ruler shows where most of its land lies, and where the other numbers you'll see come from.
| Figure | Elevation |
|---|---|
| Average of all land | 660 ft200 m |
| Highest point Inside the county, on the northwest side | 920 ft280 m |
| Lowest point Inside the county, near the middle | 370 ft110 m |
Elevation profile, west to east
30 mi west to east through Ottawa.
Topographic Map
- Location
- County in Illinois, United States
- Population
- 108,390 2024 est.
- Land area
- 1,135.1 sq mi + 13.1 sq mi water
- Density
- 95 per sq mi
- Time zone
- Central UTC−6 / −5
- Landform region
- Central Lowland
- Drains to
- Gulf of America
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Sources: U.S. Census Bureau, USGS
Nearby Places
Neighboring counties sharing a border, by average
- DeKalb County830 ft
- Lee County790 ft
- Woodford County720 ft
- Bureau County700 ft
- Livingston County680 ft
- Marshall County670 ft
- LaSalle County660 ft
- Kendall County650 ft
- Putnam County610 ft
- Grundy County590 ft
Rankings by average elevation
- Counties in Illinois40th highest of 102
- Counties in the United States2,124th highest of 3,151
Peaks and hills highest inside
- Starved Rock660 ft
- Buffalo Rock570 ft
All 69 towns in LaSalle County by typical elevation
- Mendota Township750 ft
- Mendota740 ft
- Troy Grove Township720 ft
- Meriden Township710 ft
- Miller Township710 ft
- Ransom710 ft
- Rutland710 ft
- Allen Township700 ft
- Lostant700 ft
- Groveland Township, LaSalle County700 ft
- Hope Township700 ft
- Earlville700 ft
- Earl Township700 ft
- Leland700 ft
- Adams Township700 ft
- Wenona partly690 ft
- Somonauk partly680 ft
- Richland Township, LaSalle County680 ft
- Leonore680 ft
- Osage Township670 ft
- Ophir Township670 ft
- Lake Holiday670 ft
- Dana670 ft
- Triumph670 ft
- Northville Township670 ft
- Troy Grove660 ft
- Tonica660 ft
- Eden Township660 ft
- Harding660 ft
- Cedar Point660 ft
- Freedom Township, LaSalle County660 ft
- Grand Rapids Township650 ft
- Farm Ridge Township650 ft
- Grand Ridge650 ft
- Deer Park Township640 ft
- Dimmick Township640 ft
- Otter Creek Township640 ft
- Serena Township630 ft
- Oglesby630 ft
- Serena630 ft
- Waltham Township630 ft
- Kangley630 ft
- Vermillion Township630 ft
- Wallace Township620 ft
- Brookfield Township620 ft
- Bruce Township620 ft
- Streator620 ft
- Eagle Township620 ft
- Peru Township610 ft
- Peru610 ft
- LaSalle Township610 ft
- Fall River Township610 ft
- Dayton Township610 ft
- LaSalle600 ft
- Sheridan600 ft
- Mission Township600 ft
- South Ottawa Township590 ft
- Rutland Township, LaSalle County570 ft
- North Utica570 ft
- Utica Township570 ft
- Millington570 ft
- Dayton570 ft
- Ottawa540 ft
- Wedron530 ft
- Manlius Township510 ft
- Marseilles510 ft
- Seneca510 ft
- Naplate490 ft
- Ottawa Township480 ft
How we measure
- Average: every USGS 3DEP bare-earth cell of land inside the Census county boundary (TIGER/Line, Jan 1 2026), weighted equally, on a 1 arc-second (≈100 ft, 30 m) grid. Land means the boundary minus Census area water.
- Highest and lowest: the highest land cell. Lowest: the lowest land cell; coastal ground within 3 ft (1 m) of named tidal water counts as sea level.
- Pits: the lowest point is the lowest ground outside closed hollows (quarry floors, mine pits, terrain-model artifacts): any hollow under 0.4 sq mi (1 km²), and any hollow under 2 sq mi (5 km²) whose floor is more than 100 ft (30 m) below its rim; and outside patches below sea level of under 0.4 sq mi (1 km²). The single lowest 3DEP cell, 300 ft at 41.2585° N, 89.0218° W, is in such a hollow or patch and is not counted.
- Nearby Places: neighboring counties and rankings use each one's average elevation, on its own grid, the same figure its page shows. Peaks and hills: the highest summits inside the county with at least 980 ft (300 m) of prominence, then the highest federal (GNIS) summits inside it when there are fewer than 5; each is the 3DEP top on a ~7 ft (2 m) window, or the NGS published height when a usable survey mark sits within 160 ft (50 m) of it (shown as published).
- Towns: each town's typical elevation (population-weighted median of its own 2020 blocks at 1 arc-second); a town is listed when any of its 2020 residents live in the county.
- Rounding: computed heights are rounded to 10 ft (5 m), or to 1 ft (1 m) under 100 ft; 3DEP is good to about a meter, not a foot. Published figures (NGS survey heights) are shown as their publisher gives them.
- Datum: North American Vertical Datum of 1988 (NAVD 88). NGS plans to replace NAVD 88 with a new datum (NAPGD2022); heights will then shift slightly.
- Sources: USGS 3DEP, GNIS, Watershed Boundary Dataset and physiographic provinces; U.S. Census Bureau (TIGER boundaries and water, 2020 blocks, 2024 population estimates, county adjacency); NOAA NGS survey heights; BTS time zones. All public domain.