Hiking trails provide the opportunity for people to access, experience, and appreciate natural areas, but they also pose the risk of damage by converting vegetated areas to trail, providing the opportunity for off-trail hiking, and increasing soil compaction. To assess the impact of hiking trails on the plant community of a northeastern forest ecosystem, trail width was measured, and understory vegetation was documented at the trail edge, 3 m from the trail, and 5 m from the trail every 4 km along the Northville–Placid Trail from Benson to Averyville Road in the Adirondack State Park of New York State in August 2018. Soil compaction, canopy cover, and the tree species in the canopy were documented, including from the trail itself. The mean trail width was 65.18 ± 6.06 cm. Within the 183.39 km of trail sampled, 119,533.60 ± 11,113.43 m² of forest were replaced with trail. Soil compaction was greatest in the trail and significantly lower off the trail. None of the canopies of the tree species was more likely to occur away from the trail than adjacent to or directly above the trail. Canopy cover did not differ significantly among sample locations. Cover of understory species was not significantly different near to or away from the trail. Species richness in the understory was significantly higher adjacent to the trail than 5 m from the trail, but trail width, canopy openness above the trail, canopy openness adjacent to the trail, and soil compaction were not significantly related to species richness adjacent to the trail. Understory community composition was more similar among plots within a sample location than between plots 5 m from the trail at adjacent sample locations. Collectively, the plant community outside of the trail itself is not significantly affected by the presence of the trail. The major impact of the trail is the loss of the plant community at its margins as the trail width increases. Hikers should be further educated and encouraged to use trails in ways that minimize the width of the trail to protect the ecosystem, along with trail managers continuing to increase the sustainability of the trail design.