Schoolmarm

The female teacher at a one room schoolhouse.

In rural communities of the past, particularly on the frontier, there would often not be enough children of different ages in the area to justify a school separated by grades, and insufficiently fast transportation to bring children from a wide area together every schoolday. So there would be a one-room schoolhouse, with a grand total of one teacher (usually female) presiding over a class of children of all ages and scholastic ability.

Generally, a child would attend the one-room schoolhouse from early elementary age through the minimum dropout age required by law; those seeking further education would have to go to a larger community's boarding school.

In fiction, a schoolmarm will tend to be portrayed as rather prim and proper, and will have the best diction in town. This tended to be true in Real Life as well, since most communities had strict moral and behavioral requirements in the contracts for their teachers. In many school districts, teachers had to be single and any "courtship" would raise fears that the town would lose its schoolmarm. Nevertheless, the Schoolmarm is a frequent choice for female love interest in a Western as she'll be the only single woman around who isn't in the entertainment industry. As an instructor in the arts of civilization, she also made a good Foil to a wild and footloose hero.

In male viewer-oriented stories, the schoolmarm tends to be young and pretty—sometimes suspiciously so. In stories from the schoolmarm's point of view, she may be a bit older and somewhat plain-looking, to make her eventual romantic involvement that much sweeter. If the story is from the children's point of view, the schoolmarm will often be a hatchet-faced spinster, who's not afraid of using a switch on misbehaving youths, for loose values of "misbehaving."

Since schoolteachers were usually from out of town, they would often board with the different families of their students in turn over the course of the school year. In fiction, this might be an awkward situation, the beginning of a romance with an adult member of the family, the discovery of a Big Sister Mentor for a younger member, or otherwise played for drama.

The Spear Counterpart was a "schoolmaster" (who WAS expected to be, or become, a family man). See also Two-Teacher School.

Examples of Schoolmarm include:

Anime and Manga

Yoko Littner from Tengen Toppa Gurren Lagann takes this as a job after the Time Skip.
Chie in Higurashi no Naku Koro ni.
To a degree, Mari Nikaido from Kinnikuman.

Film

Clara Clayton in Back To The Future Part III, who of course becomes the Love Interest of Doc Brown.
Butch Cassidy and the Sundance Kid: Ethel Place, Sundance's woman, is a schoolmarm who abandons her duties to go to South America with them.
Cat Ballou: Jane Fonda plays a schoolmarm turned Outlaw.
The Gunfighter has the schoolmarm as the secret wife of the lead.
Blazing Saddles had what can only be termed a subversion.

Schoolmarm: To the honorable William J. LePetomaine, Governor...
Crowd: Louder! We can't hear you!
Schoolmarm: I am sorry, I'm not used to public speaking. WE THE WHITE, GODFEARING CITIZENS OF ROCK RIDGE wish to express our extreme displeasure with your choice of sheriff. Please remove him immediately! The fact that you have sent him here just goes to prove that you are the leading asshole in the state!

Ms.Crabtree from The Little Rascals shorts.
In Rustlers' Rhapsody, a "pretty but somehow asexual young schoolmarm" is one of the features found in every single weatern town which hero Rex O'Herlihan has visited.
Michael Haneke's The White Ribbon has a Rare Male Example as one of the few sympathetic characters.

Literature

Laura Ingalls is a schoolmarm in These Happy Golden Years. Her description of what it was like is generally conceded to be fairly accurate, although the Brewster household may be dramatic license.
Holes has a schoolmarm who turns outlaw after her love interest is killed.
Anne from Anne of Green Gables goes to a one-room schoolhouse. The first teacher is male, then Miss Stacy becomes the schoolmarm. Later on, Anne herself takes on the role, and even while attending college takes temporary schoolmarm positions in the summer.
- Many of the characters did this while paying for college, including Gilbert Blythe. It becomes a plot point that he trades teaching positions with Anne to allow her to be closer to Green Gables.
- L. M. Montgomery's novels Emily of New Moon also feature such characters, of both genders.
Mandie and the Missing Schoolmarm by Lois Gladys Leppard, has the young heroine investigating a mystery that is Exactly What It Says on the Tin.
The American Girl Kirsten books have Miss Winston, who's nineteen—same age as the oldest boy in the class. She stays with Kirsten's family for a while.
Miss Read, the pseudonymous author/narrator of the Fairacre And Thrush Green novels, both Barset Shire settings, is the schoolmistress of a tiny two-room school in the village of Fairacre, and there's a similar school in Thrush Green.
Jane Eyre is a village schoolmistress for a short while (quite sensible as she'd previously been a governess- one of the few jobs acceptable to women of the landowner caste at the time); a slight variation as in her town, male and female children went to separate schools (seeing as we never meet her male counterpart, presumably St John, the local cleric, teaches the boys during the week)
Nineteen-year-old Christy Huddleston from Christy is a city-bred young woman of an affluent Asheville family who is inspired to go teach school in an impoverished Appalachian village in 1912. Needless to say, it's nothing like she thought it would be, in both good ways and bad.

Live Action TV

Minnie Pearl often played one on Hee Haw.
Captain Gunpowder is sweet on the local school mistress in Wild Boys.

Real Life

Henrietta King, wife of Richard King (called El Patron by his faithful and mostly Mexican cowhands and their families), was especially beloved. She taught the children of all the workers on the King Ranch.

Tabletop Games

A Munchkin set, The Good, the Bad and the Munchkin, which was Western-themed, had a Sidekick card called Schoolmarm, whose "book learning" could help you escape from a trap.

Theatre

Miss Minerva in The Golden Apple.

Video Games

Raine Sage of Tales of Symphonia is fairly grumpy as one of these. Of course, when one of your students is Lloyd Irving, this may be justified.
The Sierra Adventure Freddy Pharkas: Frontier Pharmacist had one of those whose last name even was Primm. However, she turns out to be the villain in the end.
In the second generation of Rune Factory 2, Mana becomes one of the only two teachers in the school built at the end of the first generation. How true she is to this trope depends on whether or not the first generation's player character married her.
Keine of Touhou is generally portrayed like this.

Web Comics

Guenevere in the Wild West part of Arthur, King of Time and Space.

Western Animation

Ms. Leading from The Marvelous Misadventures of Flapjack.
They occasionally turn up in classic animated shorts with a school setting.
Cheerilee in My Little Pony Friendship Is Magic.