Holly Pond is a large inlet of Long Island Sound on Darien's border with Stamford. The pond becomes separated from the sound by a small waterfall at low tide, so it is usually not considered to be accessible from the sound by boaters or kayakers. It is also fed by a small stream that also forms a partial border between Darien and Stamford. Due to its brackish composition, Holly Pond occasionally freezes over enough to allow ice skating in the winter, especially near the shore.