Global Range: Alliaria is native "throughout Europe from about 68o north southwards, but less common in the extreme south" (Tutin et al. 1964), occurring from England (Martin 1982) east to Czechoslovakia (Lhotska 1975), and from Sweden and Germany south to Italy, but is noticeably absent from Iceland, the Azores, Sardinia and Spitsbergen (Tutin et al. 1964). From this native range Alliaria has spread to North Africa, India, Sri Lanka (Cavers et al. 1979), and New Zealand (Bangerter 1985), as well as Canada (Cavers et al. 1979) and the United States (Gleason and Cronquist 1991, Nuzzo 1993a).
The North American range extends from British Columbia (Cavers et al. 1979, White et al. 1993) to New England (Gleason and Cronquist 1991), and from Ontario (Cavers et al. 1979) to Tennessee (Nuzzo 1993a). Alliaria was first recorded in North America in 1868 on Long Island NY, and by 1991 had spread to 30 states and 3 provinces (Nuzzo 1993a). This plant has spread exponentially since introduction in both Illinois (Nuzzo 1992b) and North America (Nuzzo 1993a).
In the United States Alliaria is most abundant in the New England and Midwestern states, but also has populations established as far west as North Dakota and Kansas, and south to Tennessee and North Carolina. Infrequent collections from western states indicate the plant may be a sporadic rather than established component of the regional flora, and/or in the process of becoming established in Utah (1971, 1983, 1984) and eastern Colorado (1952, 1958, 1966) (dates of herbarium collections). As of 1991 Alliaria had not been recorded west of the Rocky Mountains in the United States, with the exception of an 1892 record from Idaho, and a 1959 record from Portland Oregon (population absent in 1991). Alliaria is well established in Victoria B.C. and Vancouver in western Canada (Cavers et al. 1979, White et al. 1993).
In Canada Alliaria occurs in Victoria, British Columbia, and in the St. Lawrence Valley from Point Pelee in Ontario to Quebec City in Quebec (Cavers et al. 1979). Alliaria is especially abundant in southwestern Ontario, and near Toronto and Ottawa (White et al. 1993). White et al. (1993) recorded the plant as common in deciduous woods on the Canadian Shield, although 25 years earlier Cavers et al. (1979) stated the plant was noticeably absent from the region.