In fact, up to 7.4 million people may journey to the 70-mile-wide, 2,800-mile-long track where the moon will block the sun and reveal the star’s wispy corona.
That’s according to Michael Zeiler, a cartographer at Esri, a mapping data and technology company.
Zeiler has anticipated this moment since he started chasing eclipses 26 years ago. He has spent the past few years gathering data, plotting maps of the eclipse (and its surprising ramifications), and uploading them to his website, GreatAmericanEclipse.com.
Zeiler considers his “driveshed” maps some of his favorites. Like watershed maps that show how brooks, streams, and rivers move toward an ocean, his version shows where vehicles are most likely to flow toward a viewing location.
“I thought about about every populated point in the United States, and I asked the data: What is the quickest drive to totality?” Zeiler told Business Insider. “I discovered there’s going to be about one or two dozen traffic-congestion points that are going to be particularly severe.”
Here are the 12 biggest drivesheds Zeiler has identified, the cities they center on, and – by extension – the places most likely to be choked with gridlock traffic.
Zeiler’s “drivesheds” maps show the routes that drivers are most likely to take.
Zeiler said he’s given several presentations and seminars on these maps, including one to the American Association of State Highway and Transportation Officials, or AASHTO.
The maps are based on another analysis he did, which shows how close Americans are to the path of totality, and how long it’d take to make the journey.
12. Colombia, South Carolina — 5.5 million people in range
Zeiler said if you are driving to the path of totality, be sure to leave at least a day early on August 20, and plan to wait for traffic to clear for several hours after totality ends.
11. Glendo, Wyoming — 8.6 million people in range
He also recommends bringing enough food, water, toilet paper, batteries, and other supplies to last you the journey, since small-town shops may be thinly-stocked under the crush of eclipse tourism.
10. Greenville, South Carolina — 9.6 million people in range
Finding a place to go to the bathroom may also prove challenging, he added, though many cities plan to put out portable toilets.
9. Lathrop, Missouri — 12.5 million people in range
Zeiler said his maps don’t guarantee there will be terrible traffic in these drivesheds, but he considers the likelihood very high.
8. Festus, Missouri — 13.8 million people in range
“People should not casually expect to drive down on the morning of the eclipse,” Zeiler said.
7. Sweetwater, Tennessee — 20.4 million people in range
“I think the wildcard is the impact of social media,” he said. “A lot of people may feel inspired to get in a car and drive.”
6. Salem, Oregon — 25 million people in range
“This is the first solar eclipse in a heavily populated United States,” Zeiler added.
5. Goreville, Illinois — 26.2 million people in range
Zeiler said the eclipse will reach its longest point in southern Illinois.
4. White House, Tennessee — 27.1 million people in range
3. Sabetha, Kansas — 27.8 million people in range
2. Idaho Falls, Idaho — 35.8 million people in range
1. Santee, South Carolina — 74.6 million people in range
“South Carolina is the closest for one-third of the country. In particular, it’s Santee, South Carolina, which is where I-95 meets the centerline of the eclipse,” Zeiler said. “Do not go to Santee, South Carolina.”