Holtwood Environmental Preserve
It covers over near the Holtwood Dam on the Susquehanna River in Lancaster and York Counties , and includes of mesophytic old-growth forest including eastern hemlock , chestnut oak , and umbrella magnolia along the Otter Creek gorge . 
<triplet> Holtwood Dam <subj> Susquehanna River <obj> located on terrain feature <triplet> Lancaster <subj> York Counties <obj> shares border with <triplet> York Counties <subj> Lancaster <obj> shares border with