The quarantine will last at least three weeks since the missionaries were last exposed to people infected with the Ebola virus, the North Carolina Department of Health and Human Services said.
The missionaries are with Charlotte-based SIM USA. None of them are sick or have shown any signs of having Ebola, but they agree with health officials that everyone should be as cautious as possible, SIM USA president Bruce Johnson said in a statement.
"We will continue to cooperate and collaborate with them and adhere strictly to their guidelines in the return of our missionaries to the United States," Johnson said.
The aid group isn't releasing how many missionaries were in Liberia or when they will return to protect the privacy of their families.
The returning missionaries will arrive in an area of the Charlotte airport away from the public. The airport won't say exactly where the plane will be taken, according to a statement.
SIM USA aid worker Nancy Writebol is in an Atlanta hospital after contracting Ebola.