# What am I flying over? Reading the ground from 35,000 feet

> Circles mean the High Plains. A mile-square grid means you're west of Ohio. How to place yourself by the shapes on the ground, route by route.

By Derek Johnson. Updated Nov 7, 2026. Source: https://skycapapp.com/articles/window/what-am-i-flying-over/

At cruise you can see about 230 miles to the horizon in clear air, and the ground below is labeled if you know the shapes. Circles mean irrigated High Plains. A grid of roads a mile apart means you're somewhere west of Pennsylvania.

Your phone can usually find its position in airplane mode by the window, so a map downloaded before you board will settle any argument. These shapes are more fun, and they work when the seatback screen is showing an ad.

## A grid a mile on a side

Across most of the country from Ohio westward, public land was surveyed on a grid. Starting with Ohio's Seven Ranges in 1785, federal surveyors laid out townships six miles square, each cut into 36 sections of about a square mile. Roads and field edges followed those lines, and they still do. From the air you get graph paper to the horizon.

It makes a ruler. Count the road crossings and you know how many miles you've traveled, or how fast. The system never reached the original 13 states, Kentucky, Tennessee or Texas, so the pattern changes over those.

The grid also has small kinks. Lines of longitude converge toward the pole, so a square grid can't stay square, and surveyors built in correction lines where north-south roads jog sideways. Those are the little offsets you'll see in straight county roads.

## Circles

A green circle means a center pivot: a long pipe on wheels sweeping around a well. Most are half a mile across, because a quarter-mile pipe fits inside a 160-acre quarter section of that same survey grid. A 1970s NASA study of Finney County, Kansas, found 95% used that length, and some circles run to a mile. The corners of the square stay dry, which is why a High Plains field from above looks like coins in a tray.

They need groundwater, so they cluster above the Ogallala Aquifer, across western Nebraska and Kansas, eastern Colorado and the Texas Panhandle. If you're seeing lots of circles, you're probably over one of those. In summer each one is a different stage of crop, and some show as wedges where the pivot has stopped partway around.

## Rivers tell you which way you're going

The Lower Mississippi loops so hard that it has left its old loops behind as crescent lakes. The geologist Harold Fisk mapped those old channels for the Army Corps of Engineers, and his 1944 maps are worth finding if you like this kind of thing. From a plane you see the same thing live: a thick brown river, pale scars of former bends on either side, and a few oxbow lakes cut off from it.

Atlanta to Dallas is a good flight for this. The great circle crosses the river at about Greenville, Mississippi, a little past halfway, with Lake Chicot, the largest oxbow in the country, close by on the left.

North of about St. Louis the river looks different, with tree-lined bluffs and locks. It's a good clue to your latitude.

## Stripes in Pennsylvania

West of New York and Philadelphia the Appalachians show up as long, even stripes running northeast to southwest. NASA explains the color: forested ridges of tough rock, farmed valleys of softer limestone and shale. The rock was pushed from the side and buckled like a rug. The great circle from New York to Chicago runs close to State College, a little over a quarter of the way along. If you're leaving Newark or JFK heading west, watch for these stripes in the first half hour.

## Two colors of Great Salt Lake

Flights from the upper Midwest to San Francisco can pass right by Great Salt Lake. Look for a straight line across the water with a different color on each side. That's a railroad causeway built in 1959. The rivers feed only the south arm, so the north arm got far saltier, and salt-loving algae and bacteria turn it pink, while the south stays blue-green. Since 1966 the north arm has averaged about 317 grams of salt per liter, against 142 in the south.

West of the lake, the white plain is the Bonneville Salt Flats. On a great circle from Minneapolis to San Francisco, both are within about a dozen miles on the right, about two-thirds of the way along.

## Route by route

These are from great-circle calculations between the airports, and real tracks can run 50 miles or more to either side. Use the side as a good bet. [Why your flight path curves](/articles/window/why-flight-paths-curve/) explains the gap.

| Flight | What to look for | Side | Roughly when |
|---|---|---|---|
| Seattle to Los Angeles | Mount Rainier, then Mount Hood | Left, then right | First 15% of the flight |
| San Francisco to Seattle | Mount Shasta, Mount Hood, Mount Rainier | Right | From about 40% |
| Los Angeles to Seattle | Yosemite, Tahoe, Hood | Left | From about 30% |
| New York to Los Angeles | Grand Canyon, almost underneath | Right | About 85% |
| Los Angeles to Chicago | Grand Canyon | Right | About 20% |
| Phoenix to Chicago | Circles near Garden City, Kansas | Right | About halfway |
| Chicago to Denver | The Platte River and circles in Nebraska | Left | About 65% |
| Dallas to Denver | Southwest Kansas circles | Right | About 65% |
| Atlanta to Dallas | The Mississippi and Lake Chicot | Left | A little past halfway |
| Los Angeles to Atlanta | Meteor Crater, Arizona | Left | About 20% |

Clouds cancel all of this, and haze can cut that 230 miles to not much. On those days, an evening flight still has [the sunset](/articles/window/which-side-for-sunset/). At the height of a Plains summer afternoon, the puffy clouds that make [the climb bumpy](/articles/ride/why-the-climb-is-bumpy/) can sit right over the view too.

> Skycap goes through your route before you board and tells you what you should pass and which window it's out of. In the air, it shows you the sight nearest the plane. [See the window guide](/app/features/#air)

## Sources

- [NASA Earth Observatory, Crop Circles in Kansas](https://science.nasa.gov/earth/earth-observatory/crop-circles-in-kansas-5772/)
- [NASA technical report on irrigation mapping in Finney County, Kansas, from ERTS-1](https://ntrs.nasa.gov/api/citations/19730011653/downloads/19730011653.pdf)
- [US National Archives, Cartographic and Architectural Records leaflet 26](https://www.archives.gov/research/cartographic/general-info-leaflet-26)
- [Bureau of Land Management, The Public Land Survey System study guide](https://www.ntc.blm.gov/krc/uploads/940/BLM_Module2_Studyguide.pdf)
- [NASA Earth Observatory, Meandering Mississippi River](https://earthobservatory.nasa.gov/images/147001/meandering-mississippi-river)
- [US Army Corps of Engineers, Fisk map of the Mississippi meander belt](https://www.mvd.usace.army.mil/Media/Images/igphoto/2000759696/)
- [NASA Earth Observatory, Rolling Through the Appalachians](https://earthobservatory.nasa.gov/images/146570/rolling-through-the-appalachians)
- [USGS, Great Salt Lake's railroad causeway](https://www.usgs.gov/media/images/great-salt-lakes-railroad-causeway)
- [Utah Geological Survey, A Lake Divided](https://geology.utah.gov/map-pub/survey-notes/a-lake-divided-a-history-of-the-sprr-causeway-and-its-effects/)
- [Utah Division of Wildlife Resources, About the Great Salt Lake](https://wildlife.utah.gov/gslep/about)
- [White et al., How Do Changes to the Railroad Causeway in Utah's Great Salt Lake Affect Water and Salt Flow? PLOS ONE, 2015](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4671733/)