The mother and her children were waiting in line early Friday at the Greyhound bus station in downtown Dallas. A Greyhound spokeswoman tells The Dallas Morning News that the mother appeared to suffer a medical emergency and was taken to an area hospital, where she died.
The woman's name and the cause of her death have not been released.
The family was traveling from Mississippi to Oregon. The children stayed with Greyhound officials until police officers took them to Child Protective Services. Officials are trying to contact the children's father.
Greyhound says it will take the children to Oregon for free.