Garrett Island

Garrett Island is an island located in Cecil County, Maryland, 1.8 miles from the mouth of the Susquehanna River, directly west of Perryville and north of Havre de Grace. It is managed by the U.S. Fish and Wildlife Service as part of the Blackwater National Wildlife Refuge. The island is crossed by the CSX Susquehanna River Bridge on the north side and the Thomas J. Hatem Memorial Bridge on the south side.

The Cecil Observer, quoting the Chesapeake Bay Journal, describes the geologic history of Garrett Island: "'Garrett Island is the geologic remnant of what was once an offshore volcano in an ancient sea. The rocky high ground on the island's west side is the remains of the volcanic core. Basalt and quartz formed by the volcanic activity are still present.'" Garrett Island is the only rocky island in the tidal waters of the Chesapeake Bay.

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