Approximately 7.4 million Americans may travel to the path of totality, where the moon's darkest shadow will cut across the country. But this mass migration may overwhelm small towns and cities with record tourism - and choke key roadways with gridlock traffic.
That's according to an analysis by Michael Zeiler, a cartographer at the mapping data and technology company Esri, and an eclipse chaser of 26 years.
"People should not casually expect to drive down on the morning of the eclipse," Zeiler told Business Insider.
In Oregon, which will be the first US state to see the moon blot out the sun, it seems the mass influx of vehicles for the eclipse may have already begun.
A video taken on Wednesday by a frustrated-sounding central Oregon resident, which KAPP-KVEW Local News posted to its Facbook page, shows a line of cars that stretches for all 4 minutes and 32 seconds of the video, and for at least 5 miles of roadway.
"This is all heading into Prineville on a Wednesday, all the way up the mountain," she said in the video, which she recorded around 11:32 a.m. PDT. "There is no accident. This is all for the lovely eclipse that is happening, and everyone trying to get into their camping spots."
She added: "Luckily, I'm heading the other direction. ... The cars next to us are going roughly 5 miles per hour, if not completely stopped."
Prineville, Oregon, is located about 120 miles southeast of Salem, Oregon - a location that Zeiler expects to be one of the sixth-most trafficked solar eclipse viewing locations in the country.
About 25 million Americans might determine the latter town is the quickest place to travel to see totality, based on Zeiler's analysis.
Traffic on main roadways throughout the region seemed to be decent on Friday morning, according to Google Maps data, but Zeiler expects most people to hit the roads this weekend - so mid-week traffic jams aren't an encouraging sign.
Zeilers advises those who are making the journey to bring all the food, water, toilet paper, and other essentials they would need in case small-town stores have their shelves emptied by hordes of eclipse chasers.
"You need to plan to be completely self-sufficient," he said.