The presence of the ant subfamily Myrmeciinae is established in the Early Eocene (Ypresian) Okanagan Highlands localities of Horsefly River, Falkland, McAbee (British Columbia, Canada) and Republic (Washington state, United States) and in the Mo-clay Ølst and Fur Formations (Denmark). Nine new species in four new genera (three orthotaxa: Ypresiomyrma n. gen., Avitomyrmex n. gen., and Macabeemyrma n. gen.; one parataxon: Myrmeciites n. gen.) are described. Seven are placed in the Myrmeciinae: Ypresiomyrma orbiculata n. sp., Ypresiomyrma bartletti n. sp., Avitomyrmex elongatus n. sp., Avitomyrmex mastax n. sp., Avitomyrmex systenus n. sp., Macabeemyrma ovata n. sp., and Myrmeciites herculeanus n. sp.; two further species are tentatively placed in the subfamily, Myrmeciites (?) tabanifluviensis n. sp. from Horsefly River, and Myrmeciites (?) goliath n. sp. from McAbee. Two further myrmeciine ants are treated as Myrmeciites incertae sedis, a male from Falkland and a female (worker or queen) from Republic. Pachycondyla rebekkae Rust and Andersen, from the earliest Ypresian of Denmark, is reassigned to the genus Ypresiomyrma, within the Myrmeciinae. The fossil record indicates a northern hemisphere origin of the subfamily. The presence of Ypresiomyrma in Denmark and British Columbia further reflects the well-documented Paleogene cross-North Atlantic distributions of biota. The known fossil record of the Myrmeciinae is restricted to the Eocene.