Mrs. Hale is the wife of Lewis Hale; a farmer who is the only witness to the the aftermath of the murder of John Wright by his estranged wife, Minnie.
A character with no first name, Mrs. Hale is a fellow farm wife, just like Minnie. There is no direct description of her but, her behavior throws in many clues as to her life and experience. Equally the audience can infer, from the very vocal opinions that she emits, how she feels about the entire thing.
It is evident that Mrs. Hale is a traditional farm wife who, by default, is not only her husband's wife, but also his "right hand". She shows up with Lewis to conduct the search at Minnie Wright's house, and she obediently collected Minnie's belongings as asked. She takes her role as a farm wife seriously, as she defends this particular fact about Minnie's own life when the district attorney laments the state of the house implying that Minnie does not work hard enough at home. Phrases such as
there's much to be done in a farm
Farmer's wives have their hands full...
are often expressed in defense of women just like her and Minnie.
This tendency to defend herself "stiffly" from the jabs of the men makes Mrs. Hale a woman that, in comparison to Mrs. Peters, seems more free of thought and speech, regardless her being less "sophisticated" than the other woman.
Mrs. Hale displays a strong sense of loyalty toward Minnie Wright also because, as a fellow farm wife, she knows that farming is a thankless job, often accompanied with terrible isolation. Knowing this makes her feel guilty about not having "been there" for Minnie when the latter needed it the most. Hence, Mrs. Hale had sensed that something terrible was going on in the Wright household; yet, as her obedience as a wife dictates, she chose to stay "out of it".
In the end, Mrs. Hale is willing to stop at nothing to defend Minnie. From putting the circumstantial evidence together, to the surreptitious "fixing" of the erratic stitching, we see an understanding, and extremely loyal woman. The toughness of the farm life, her strong grip on reality, and the realization that women DO have limits is what makes the substance of Mrs. Hale as a very influential character in the play.