The Maine State Nurses Association is a professional organization and trade union of registered nurses in the U.S. state of Maine.
Superintendent of the Children's Hospital in Portland, Edith Soule, was its first president.
One of its first acts was to support a bill for the registration and professionalization of nurses, which passed the Maine Legislature in 1915.
It formed its first collective bargaining unit at Eastern Maine Medical Center in the 1970s.
MSNA/NNOC/NNU represents about 4,000 nurses and other caregivers from Portland to Fort Kent, including the nurses at Maine Medical Center in Portland.