In1912 Henry Flagler rode the first train into Key West, marking the completion of the Florida East Coast (FEC) Railway's Over-Sea Railroad connection to Key West and the linkage by railway of the entire east coast of Florida. The FEC was the product of Flagler's resources and imagination. Flagler's construction of hotels at points along the railroad and his development of the agricultural industry through the Model Land Company established tourism and agriculture as Florida's major industries. Amazingly, Flagler accomplished these feats after retiring from his first career. Flagler had already founded the vast empire of Standard Oil with partners John D. Rockefeller and Samuel Andrews, before becoming interested in Florida.

When Flagler first visited Florida in 1878, he recognized the state's potential for growth but noticed a lack of hotel facilities. Flagler returned to Florida and in 1885 began building a grand St. Augustine hotel, the Hotel Ponce de Leon. Flagler realized that the key to developing Florida was a solid transportation system and consequently purchased the Jacksonville, St. Augustine & Halifax Railroad. He also noticed that a major problem facing the existing Florida railway systems was that each operated on different gauge systems, making interconnection impossible. Shortly after purchasing the Jacksonville, St. Augustine & Halifax Railroad, he converted the line to a standard gauge.

The Jacksonville, St. Augustine & Halifax Railroad served the north eastern portion of the state and was the first railroad in what would eventually become the Florida East Coast Railway Company. Before Flagler bought the organization, the railroad stretched only between South Jacksonville and St. Augustine and lacked a depot sufficient to accommodate travelers to his St. Augustine resorts. Flagler built a modern depot facility as well as schools, hospitals and churches, systematically revitalizing the largely abandoned historic city.

Flagler next purchased three additional existing railroads: the St. John's Railway, the St. Augustine and Palatka Railway, and the St. Johns and Halifax Railroad so that he could provide extended rail service on standard gauge tracks. Through the operation of these three railroads, by spring 1889 Flagler's system offered service from Jacksonville to Daytona. Continuing to develop hotel facilities to entice northern tourists to visit Florida, Flagler bought and expanded the Hotel Ormond, located along the railroad's route north of Daytona.

Beginning in 1892, when landowners south of Daytona petitioned him to extend the railroad 80 miles south, Flagler began laying new railroad tracks; no longer did he follow his traditional practice of purchasing existing railroads and merging them into his growing rail system. Flagler obtained a charter from the state of Florida authorizing him to build a railroad along the Indian River to Miami and as the railroad progressed southward, cities such as New Smyrna and Titusville began to develop along the tracks.

By 1894, Flagler's railroad system reached what is today known as West Palm Beach. Flagler constructed the Royal Poinciana Hotel in Palm Beach overlooking Lake Worth. He also built The Breakers Hotel on the ocean side of Palm Beach, and Whitehall, his private 55-room, 60,000 square foot winter home. The development of these three structures, coupled with railroad access to them, established Palm Beach as a winter resort for the wealthy members of America's Gilded Age.

Palm Beach was to be the terminus of the Flagler railroad, but during 1894 and 1895, severe freezes hit the area, causing Flagler to rethink his original decision not to move the railroad south. To further convince Flagler to continue the railroad to Miami, he was offered land from private landowners, the Florida East Coast Canal and Transportation Company, and the Boston and Florida Atlantic Coast Land Company in exchange for laying rail tracks.

In September 1895, Flagler's system was incorporated as the Florida East Coast Railway Company and by 1896, it reached Biscayne Bay, the largest and most accessible harbor on Florida's east coast. To further develop the area surrounding the Miami railroad station, Flagler dredged a channel, built streets, instituted the first water and power systems, and financed the town's first newspaper, the Metropolis. When the town incorporated in 1896, its citizens wanted to honor the man responsible for the city's development by naming it, "Flagler." He declined the honor, persuading them to keep the city's old Indian name, "Miami."

Never one to rest on his laurels, Flagler next sought perhaps his greatest challenge: the extension of the Florida East Coast Railway to Key West, a city of almost 20,000 inhabitants located 128 miles beyond the end of the Florida peninsula. Flagler became particularly interested in linking Key West to the mainland after the United States announced in 1905 the construction of the Panama Canal. Key West, the United States' closest deep-water port to the Canal, could not only take advantage of Cuban and Latin America trade, but the opening of the Canal would allow significant trade possibilities with the west.

The construction of the Over-Sea Railroad required many engineering innovations as well as vast amounts of labor and monetary resources. At one time during construction, four thousand men were employed. During the seven year construction, five hurricanes threatened to halt the project. Despite the hardships, the final link of the Florida East Cost Railway was completed in 1912, the year before Flagler's death.

Linking the entire east coast of Florida, a state that at the time was largely an uninhabited frontier, demanded a great deal of foresight and perseverance. Nearly a century later, the effects of Henry Flagler's incredible accomplishments can still clearly be seen throughout Florida.