This work details the structure and composition of the woody plant community of a gallery forest located in the La Silla River, between Monterrey and Guadalupe urban areas in Nuevo León, Mexico. For the analysis, the woody vegetation was categorized into upper and lower strata. The upper stratum maximum height was 38 m, and the canopy cover was 100%. The canopy consisted of 22 species from 16 families, of which seven species represented 82.3% of the importance value index (IV); Taxodium huegelii had the highest IV (34.32%). The lower stratum maximum height was 2.5 m, and the cover was 48%. Thirteen species from 10 families were identified, five of which reached 81.3% of the IV; Ricinus communis had the highest IV (23.42%). The plant community diversity was 3.8 and 2.29, based on Margalef and Shannon indices, respectively. As one finding in the present study, it can be stated that the main threat is the presence of widely distributed exotic species such as Ricinus communis and Leucaena leucocephala, with high importance values. However, the presence of a well-established tree stratum, as well as the presence of species typical of the gallery forest, suggest a good state of conservation of this gallery forest. The present results highlight the importance of studying the composition, structure, and diversity, taking into consideration the flora of floristic provinces, as an analytic strategy for the diagnosis of riparian lentic community health.