Chicago's travel order was updated once again Tuesday adding three states to its quarantine list, including some that were recently removed.
The states added to the list include Hawaii, Nebraska and North Carolina.
Last week, North Carolina had been removed from the quarantine list and Nebraska had previously also been removed.
The emergency order now requires anyone visiting or returning to the city from one of 22 locations to self-quarantine for 14 days.
As of last week, the list stood at 19 U.S. states and territories.
Florida, California and Puerto Rico may soon be removed from the list as their numbers dropped below the threshold, according to the order, but will need to stay under the required metrics for another week to be officially removed.
Indiana, on the other hand, has reached the required metrics and will likely be added to the list soon, according to Chicago Department of Public Health Commissioner Dr. Allison Arwady.
The city's travel order is evaluated every Tuesday, with any changes taking effect the following Friday.
States are added to the list if they have "a case rate greater than 15 new COVID-19 cases per 100,000 resident population, per day, over a 7-day rolling average." If they fall below that threshold, they could be removed as well.
Chicago's travel order first began on July 6.
The states currently included are: Alabama, Arkansas, California, Florida, Georgia, Hawaii, Idaho, Iowa, Kansas, Louisiana, Mississippi, Missouri, Nebraska, Nevada, North Carolina, North Dakota, Oklahoma, South Carolina, South Dakota, Tennessee and Texas, as well as Puerto Rico.
Arwady said travelers entering or returning to Chicago from "states experiencing a surge in new COVID-19 cases" will need to quarantine "for a 14-day period from the time of last contact within the identified state." Essential workers could be exempt from the quarantine requirement, however, as long as their employer certifies their work in writing.
The order is set to remain in effect until further notice.
New York and New Jersey are also asking visitors from several states, including Illinois, to quarantine themselves for two weeks.
Still, outside of Chicago, Illinois Gov. J.B. Pritzker said the state likely won't require residents who travel to and from neighboring states to quarantine for two weeks solely because of that travel.
But Illinois' Department of Public Health has released a "travel map" indicating which states are a "higher risk" for travelers.
The state's map uses the same criteria as Chicago's travel order for determining the states that are deemed to be an increased risk.
“Travel may increase the chance of becoming infected and spreading COVID-19,” IDPH Director Dr. Ngozi Ezike said in a statement. “To help inform residents where they might be at greater risk of being exposed to COVID-19 when they travel, IDPH has launched a map that clearly shows states and other countries where case rates are elevated. While staying home is the best way to protect yourself and others from COVID-19, we know that it may not be possible to avoid all travel. We encourage people who are traveling, whether for work or otherwise, to check out the map before making plans.”