In the United States, where terrain was often rugged and infrastructure scarce, semaphore never reached the scale it did in Europe. But it existed. And it mattered. In 1813, during the War of 1812, Irish-born engineer Christopher Colles designed a semaphore line between New York City and Sandy Hook, New Jersey, to warn of British ships. His system used a combination of moving arms and numerical dials, manually operated to transmit coded messages across 47 miles of coastline. Though short-lived, the project proved that visual signaling could work in American conditions.
Colles himself was a polymath—an engineer, cartographer, and inventor who had previously proposed waterworks, roads, and navigation projects for New York State. His semaphore towers were likely manned by local volunteers or militia members trained in the codebook. These were ad hoc installations, improvised in times of threat and removed when the danger passed.
Which brings us again to the Hudson.
The Hudson River has always been more than water. It is a corridor of commerce, a defensive spine, a stage for revolution. The steep hills along its banks are natural lookouts. During the Revolutionary War, signal fires burned from the Palisades to Mount Beacon. Smoke by day, fire by night. A language older than code.
By the early 19th century, as the country once again braced for conflict, planners turned back to those same ridgelines. The War of 1812 had raised serious concerns about British naval attacks along the Atlantic coast and possible incursions up the Hudson River, a vital corridor linking New York City to the interior. In response, military and civilian leaders explored ways to modernize early warning systems beyond the traditional beacon fires used during the Revolution. Proposals circulated for visual signaling networks between New York City and Albany, modeled in part on European semaphore systems then in use. While definitive maps are lacking, circumstantial evidence remains. Place names like Telegraph Road, Signal Hill, and Beacon Mountain appear across the Hudson Valley. These are not just poetic names, they likely reference real infrastructure, though direct links to semaphore use are difficult to confirm.
From Breakneck Ridge to Storm King and the highlands of Columbia County, the topography suggests a natural line-of-sight corridor. On clear days, observers at Mount Beacon can see for miles. These peaks were not chosen at random. They were chosen because they could see.
Mount Beacon itself was named for its wartime signaling role. Later, it hosted radar installations, weather instruments, and broadcast towers. It’s reasonable to believe it may have served as a relay point during the semaphore era as well, though no formal record of such a system survives.