Canoers heading to Minnie’s Island from Lockhouse 8 earlier this year. Credit: Courtesy of Minnie’s Island Community Conservancy.

The Potomac is one of America’s most storied rivers, from its headwaters in West Virginia, through the nation’s capital, to its journey’s end at the Chesapeake Bay. In 1608, Capt. John Smith and his band of explorers were the first white men to sail the river above present-day Washington, D.C., traveling upstream until their small boat could go no farther, their progress blocked by islands that began to appear in the waters. 

Geographically, Montgomery County lies along the fall line where the hilly Piedmont Plateau breaks into the flatlands of the Atlantic Coastal Plain, causing the upheaval of massive stones—the most famous being Great Falls, where the Potomac’s waters rush wildly before flattening downstream. Along the more placid sections of the river in Montgomery County rose more than 30 islands, ranging from small, tree-dotted rock outcroppings to expanses of 100 acres or more. 

Ownership of the islands, and the Potomac River, was a point of contention from the early days of the Virginia and Maryland colonies. The courts eventually determined that Maryland owned the river. Those islands above and below the falls became part of Montgomery County.

Mason Island, near the Frederick County line, was the largest, big enough to be cultivated by a succession of farmers. Barges carried produce across the water to the banks of the Potomac, where wagons finished the journey to market. With the construction of the Chesapeake and Ohio Canal, which began in 1828, island farmers had access to a direct waterway, entering the river through connecting channels, bypassing the falls and allowing boats to easily carry produce to Georgetown, where waiting ships carried the goods to other markets.

As the Potomac made its way south from Mason Island to the District, it ran past, at one time, 39 islands large enough to be given names. Many were identified by owners or nearby onshore residents. The Beall, Clagett, Conn, Offutt, Olmsted, Perry, Selden and Watkins families were among those who gave their names to the islands. Others were identified by prominent natural features, such as Grapevine, Elm, Sycamore and Cedar islands. Some, like the appropriately named Tenfoot Island, were mere ripples in the water.

By the end of the 19th century, people began to build fishing camps and summer cabins on the larger islands south of Great Falls. Cabin John Island featured a small establishment serving drinks to visitors.

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South of Cabin John Island was Sycamore Island, which had become a favorite spot to boat and relax by the middle of the 19th century. The private
Sycamore Island Club was founded in 1885, offering members fishing, canoeing and swimming in the Potomac. Today, the still-existing club owns Sycamore Island and the undeveloped Rupperts Island, a natural habitat for cormorants, geese and other wildlife. Then, as now, club members reached the island by boat or a hand-drawn ferry.

Massive storms would swell the Potomac throughout the 20th century, flooding the islands, sweeping away farmhouses, summer camps and fishing lodges. Today, little is left to suggest that the islands were once inhabited. Yet some of them have found modern-day uses. Adventure Island, run by Calleva, offers young campers the opportunity to paddle out to the island and spend the day exploring creeks, swimming and canoeing. Minnie’s Island, off the C&O Canal near Lockhouse 8, is being rehabilitated by the Minnie’s Island Community Conversancy, a volunteer group that is clearing trails, identifying wildlife and rebuilding an old cabin there. And Sycamore Island, with its historic buildings, retains a hint of what recreational island life in Montgomery County once was.