In Poland, the mountainous and hilly regions until recently were territories with unbalanced and poor diet quality, especially in early spring. Wild edible plants were or remain influential in supplementing a human diet. One of the earliest wild edible plants to appear in the growing season, characteristic of a broad swath of Europe from Ukraine to Germany, remains wild (ramsons) garlic (Allium ursinum L.). This paper assesses the impact of the vegetation site and preservation methods on the content of chlorophylls, β-carotene, vitamin C, total polyphenols, and antioxidant activity (ABTS, DPPH, and FRAP) of wild garlic leaves. In addition, the connection between its genome pattern and chemical composition was assessed. The plants were collected in three locations in the Carpathian foothills, and the reference sample was plants collected in the lowlands. The site from which the raw material was harvested has a statistically significant effect on the chemical composition of the preserved leaves of wild garlic. The profiles of the analysed components differed in the material from a different site. Wild garlic leaves from mountainous areas (400–600 m above sea level) were characterized by a higher content of the analysed ingredients than leaves obtained from lowland sites (200 m above sea level). Moreover, the material from the lowlands had a different genetic pattern from the leaves from the mountainous areas.