Contour Lines in Rock Island County, Illinois
Rock Island County, Illinois rises to 810 ft, 524 ft above its lowest ground. The map below draws contour lines across the county at the same intervals the Land Owl app uses.
Rock Island County, Illinois at a glance
| Highest elevation | 810 ft |
|---|---|
| Lowest land elevation | 286 ft |
| Total relief | 524 ft |
| Average elevation | 664 ft |
| Average slope | 4.3% |
| Land under a 5% grade | 69.9% |
| Land steeper than 15% | 4.9% |
Rock Island County, Illinois is home to 141,869 residents. Land Owl's contour line layer records the following within the county boundary — Highest elevation: 810 ft. Lowest land elevation: 286 ft. Total relief: 524 ft. Average elevation: 664 ft. Average slope: 4.3%. Land under a 5% grade: 69.9%. Land steeper than 15%: 4.9%. The figures on this page are derived from the same data the map renders, so they always agree. A free Land Owl account adds parcel boundaries, ownership records, flood zones, soils and wetlands over the same view.
Frequently asked questions
- How high is Rock Island County, Illinois, and how steep is it?
- The high point of Rock Island County, Illinois is 810 ft and its lowest land sits at 286 ft, with an average slope of 4.3% across the county. Elevations are measured from the USGS bare-earth elevation model inside the county boundary.
- Is this topographic map free to use?
- Yes. This map is free to view. A free Land Owl account unlocks the other data layers, parcel boundaries and ownership records.
- Where does this data come from?
- Land Owl draws contour lines from the USGS 3D Elevation Program (3DEP) bare-earth digital elevation model, served through AWS Terrain Tiles, and the elevation figures on this page are measured from that same model inside the county boundary. It is a screening surface at roughly 30-foot ground resolution, not a survey: it will not find a small berm, a ditch or a cut, and no lender, engineer or building department will accept it in place of a site survey.
- What contour interval does this map use?
- The interval changes with zoom, the way it does in the Land Owl app: 50-foot contours with a 200-foot index line when you are looking at the whole county, tightening to 10-foot and then 5-foot contours as you zoom into a parcel.
- Can I use these contours to plan a build or a drainage design?
- To shortlist land, yes — this is enough to tell a flat lot from a steep one and to see which way water leaves a property. To design on, no. These are bare-earth contours off a national elevation model at roughly 30-foot ground resolution; a driveway grade, a pad elevation or a drainage plan is drawn off a site survey.
See every layer over Rock Island County
Parcel boundaries, ownership, flood zones, soils, wetlands and topography on one map.
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