REACH Air Medical Services, an air ambulance service based in Santa Rosa, has expanded its operations into the Midwest.

The company has acquired Air Angels, Inc., a full-service air and ground critical care transportation provider based in Bolingbrook, Ill. near Chicago.

The purchase price was not disclosed.

Air Angels will maintain its name and continue its current services. Its former CEO, Michael Dermont, will oversee the operation.

REACH began providing helicopter air ambulance services in Northern California in 1987. Since that time, it has expanded from one to nine bases throughout Northern California and Oregon.

REACH Air Medical Services is a subsidiary of REACH Medical Holdings, Inc.