Family and Situation
Mrs. Jenkinson is the live-in companion (and likely former governess) of Anne de Bourgh. Mr. Collins tells us that she “supervised her [Miss de Bourgh’s] education and has remained with the family,” suggesting that either the woman does not mind being bossed around by Lady Catherine or has no other options.
We know that there is a pianoforte in her room at Rosings Park which Lady Catherine offers to let Elizabeth use. Given this information, we can guess that she was once a woman of some accomplishment and that she either became a governess after being widowed or is simply a spinster and took on the title of “Mrs.” as an honorific.
Appearance
Mrs. Jenkinson never has dialogue in the novel, so the information about her is somewhat limited. Maria Lucas describes her as an “old lady” and the narrator says that in her “appearance there was nothing remarkable.”