Book one of the Literature/FrontierMagic series by Creator/PatriciaCWrede. It's set in an AlternateUniverse where magic is a normal part of life for the settlers on the Columbian (their version of America) frontier.

Eff Rothmer was born a thirteenth child. Her twin brother, Lan, is the [[MagicalSeventhSon seventh son of a seventh son]]. This means he's [[TheChosenOne supposed to possess amazing talent]] -- and she's supposed to bring only bad things to her family and her town. Undeterred, her family moves to the frontier, where her father will be a professor of magic at a school perilously close to the magical divide that separates settlers from the beasts of the wild.

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!! This book provides examples of:
* TheAce: Lan
* AdultsAreUseless: Averted. The adults are the people Eff, Lan and William go to with concerns for good reason.
* AgeCut: Happens a few times with Eff going through a few years in just a paragraph and then resuming the narrative
* AllOfTheOtherReindeer: Eff's aunts, uncles and cousins.
* AlternateHistory: Nineteenth century American frontier with magic, dragons and wooly mammoths
* AlternateUniverse
* AlwaysChaoticEvil: Thirteenth children, according to Eff's aunts and uncles
* AmazingTechnicolorWildlife: Jeweled minks, silverhoofs and other wildlife from the Plains
* AncientArtifact: The wooden pendent seems like this
* ApologizesALot: Eff
* ArbitrarySkepticism: Professor Rothmer thinks Eff's aborted attempt to blow up her uncle was a fluke, even though he's presumably seen stranger things from his students.
* AsYouKnow: Eff starts the book by talking about how everyone knows seventh sons are special.
* AudienceMurmurs: How the Rationalists crowd in Oak River showed its approval of Eff being willing to go out without protection spells
* BadassLongcoat: Seemingly a requirement for living west of the Great Barrier Spell
* BadPowersBadPeople: Eff's aunts and uncles seem to think this is at play
* BecauseDestinySaysSo: Eff spent years being sure that she was going to go bad one day
* BerserkButton: Don't pick on Eff when Lan is around. Or any of her other siblings, for that matter.
* BigDamnHeroes
* BoardingSchool: Lan and William go off to one in the East.
* BornLucky: Professor Rothmer and Lan
* BrattyTeenageDaughter: Rennie is this for a long time
* BreakTheCutie: The first five years of Eff's life.
* BugCatching
* BullyingTheDragon: Eff's aunts, uncles and cousins spent the first five years of Eff's life bullying her
* CantGetAwayWithNuthin: Poor Eff can't even get away with things she didn't do!
* CharacterWitness: William serves as this for Eff
* ChildProdigy: Lan
* ChildrenAreInnocent: Examined. Eff treated as a monster by her extended family for the first five years of her life, despite never doing anything to deserve it. Years later, when she catches herself wondering whether her sister's possible death would change her status as an [[ThirteenIsUnlucky unlucky thirteenth]], her first reaction is to believe that her aunts and uncles were right about her all along.
* CloseKnitCommunity: Mill City, as they are assured as soon as they arrive.
* ConflictKiller: Lan's double-seven status
* TheConscience: Eff is this for Lan sometimes.
* ContainmentField: The Great Barrier Spell is this writ large
* CoolTeacher: Miss Ochiba and Wash, to a lesser extent
* CryingLittleKid: Poor Eff
* CubCuesProtectiveParent: Wash's rule of thumb when in the settlement territory
* DeterminedHomesteader
* DeterminedHomesteadersWife
* DontSplitUsUp: An unusual example, as it was only for the month or so that the family stayed in their old hometown, but Lan insists that he and Eff stay together so he can protect her.
* DoomMagnet: Eff thinks she's this, among other things, thanks to her extended family's abuse.
* {{Elopement}}: [[spoiler:Rennie and Brant]]
* EnergyAbsorption: [[spoiler:The grubs, beetles and mirror bugs]]
* EnfantTerrible: Another thing the extended Rothmer family suspected Eff of having been
* EthnicMagician: Miss Ochiba and Wash, who use Aphrikan (aka African) conjure magic rather than the Avrupan (aka European) magic of almost everyone else
* EvilUncle: Earn
* {{Expospeak}}: The professors do this occasionally. William and Lan get in on it too, after they go East for school.
* FamilyDisunion
* FantasticTimeManagement: Quick-drying spells, speed-travel spells and more
* FantasyForbiddingFather: Professor Graham
* FantasyCounterpartCulture: Played with. As the setting is an AU Earth, the lands and cultures are pretty much the same, but they all have different names.
** Columbia is America, Aphrika is [[CaptainObvious Africa]], Avrupa is Europe, Ashia is Asia, Cathay is China, among others
* FeatheredFiend: Terrorbirds
* FlatEarthAtheist: The Rationalists, to some extent, though instead of not believing in something that's there, they decide to go without it (meaning going about their lives on the frontier without the use of magic to protect them.)
* FoolishSiblingResponsibleSibling: Lan and Eff, respectively
* FreeRangeChildren
* FriendlyRivalry: Lan and William have one going when they come back from boarding school.
* FunctionalMagic
* FundraiserCarnival
* GentlemanAdventurer: Wash is an interesting variant of this, as is Dr McNeil.
* GoodParents: Daniel and Sara Rothmer
* GuiltComplex: Eff
* HarmfulToMinors: The extended Rothmer family.
* HannibalLecture: Uncle Earn tries to give one to Eff. It doesn't end well.
* HeadInTheSandManagement: The Settlement Office, particularly under Mr Harrison.
* HeldBackInSchool: Eff after having rheumatic fever.
* HereThereBeDragons
* HermeticMagic: Avrupan magic
* HeroicSafeMode: Caused by Professor Rothmer with a magic-dampening spell after Eff's argument with Earn
* HigherEducationIsForWomen: According to settlers, at least
* HistoricalDomainCharacter: Ben Franklin was a double-seventh son in this world. He and Thomas Jefferson, also a double-seven (Something neither was in our world - they were a tenth and an only son, respectively), created the Great Barrier Spell to keep the United States of Columbia safe from western wildlife.
* IJustWantToBeNormal: Eff
* IllGirl: Eff is this for a while after fighting off rheumatic fever
* IneptMage: Eff, after the incident with Uncle Earn
* IntergenerationalFriendship: Eff and Wash, also Eff and Prof Jeffries.
* IstanbulNotConstantinople: Columbia is America, Gaul is France, etc.
* IvyLeague
* JustThinkOfThePotential: Brant about a successful Rationalist settlement opening up the rest of the West to settlement.
* KickingAssInAllHerFinery
* KidsAreCruel: Eff's cousins torment her as a child.
* LadyOfAdventure: Eff
* LamarckWasRight: Seventh and double-seventh sons are an odd case of this
* LastFertileRegion: Oak River
* LectureAsExposition
* TheLoad: Mr Harrison, even before he's named in the book
* MaamShock
* MagicAIsMagicA: Just like magic B and magic C
* MagicIsAMonsterMagnet
* MagicalNegro: Played with in both Miss Ochiba and Wash
* MagicalSeventhSon: Lan. It isn't until the third book that people realize that Eff, as the seventh ''daughter'' of a seventh son, also applies.
* MagicTool: Wash's pendant
* MagicVersusScience: Averted. Magic is treated as a science.
* MamaBear: Mrs Rothmer
* MassivelyNumberedSiblings: Eff has seven brothers and six sisters. Her father has six brothers and several sisters.
* AMinorKidtroduction
* MissingMom: William's mother is an invalid, never shows up in story, and is implied to be unable to have any role in William's raising
* MRSDegree
* MugglesDoItBetter: Rationalist engineers. Also Brant on the McNeil Expedition
* MySecretPregnancy
* {{Neet}}: Rennie
* NoPlansNoPrototypeNoBackup: Played with. Jefferson and Franklin did leave behind their notes for the Great Barrier Spell, but since Franklin was self-taught and Jefferson tended to assume that everyone was as well read as he was, nobody can make any sense out of them.
* NumerologicalMotif: 7 and 13
* ObstructiveBureaucrat: Mr Harrison
* OurDragonsAreDifferent: They produce steam.
* OvershadowedByAwesome
* ParentsKnowTheirChildren: Daniel and Sara Rothmer do, at least. Professor Graham, however, does not.
* PolarOppositeTwins: Lan and Eff
* PowerIncontinence
* PowerLimiter:
* PowerTrio: Eff, Lan and William are ego, id and superego, respectively.
* PrimAndProperBun: Miss Ochiba
* TheProfessor: Several, Eff's father being the main example
* ReasonableAuthorityFigure: Eff's parents and mentors
* ScrewDestiny: Not Eff's response, but everyone else's
* SettlingTheFrontier
* SheIsAllGrownUp
* TheSheriff
* ShutUpHannibal: Eff to Uncle Earn
* SilverHasMysticPowers: As does sulfur, and other minerals and metals.
* SkipOfInnocence
* SlaveLiberation: How Miss Ochiba's parents met.
* SouthernFriedPrivate: Wash has a Southern drawl and, like many other black men, fought for the North in the Secession War.
* SpannerInTheWorks: Allie is this for Rennie's plan to [[spoiler:run away with Brant]]
* SternTeacher
* SupernaturalSensitivity: Aphrikan world-sensing
* SynchronizedSwarming: Swarming weasels
* TerminallyDependentSociety: The Rationalists believe society is too dependent on magic
* TextileWorkIsFeminine: The Rothmer women are in charge of laundry and mending clothes
* ThirteenIsUnlucky: Why Eff's extended family dislikes her.
* TooDumbToLive: Mr Harrison, Uncle Earn
* TroubledChild
* TwinDesynch: Happens a bit after Eff spent a year bedridden
* TwinTelepathy: Averted, later invoked by William
* UnableToSupportAWife
* UnequalRites: Avrupan mages are called magicians while Aphrican mages are conjurefolk and leaders Hijero-Cathayan covens are called adepts.
* TheUnfavorite
* UnlikelyHero
* UnstoppableRage: Eff fears this is what her magic will become
* WalkingTechbane
* TheWatcher: Wash functions as this for a little while.
* {{Whatevermancy}}
* WickedWeasel: Swarming Weasels
* WideEyedIdealist: Professor Rothmer considers Brant to be this to some extent
* WildMagic: What Aphrikan magic uses
* TheWildWest
* WithGreatPowerComesGreatResponsibility: Double-seven powers
* WonderChild: Lan, as a double-seventh son
* YouKnowWhatTheySayAboutX
* YoungestChildWins: Subverted. Lan is supposed to be the great magician of the family, but [[spoiler:Eff]] is the one that saves the day