Settlement began in the late 1870s in the form of Blake Station on the overland mail route between Salina, Utah, and Ouray, Colorado. The first permanent settlers of European stock were the families of Thomas Farrer and Matthew Hartman. The Farrers played a leading role in the community for several decades, operating a general store, a bank, and a ferry service.
The completion of the Denver and Rio Grande Western Railway in 1883 made Green River a shipping point for livestock and mining equipment and supplies. The railroad built an engine house, switching yards, and a three-story hotel called the Palmer House. The influx of railroad workers gave the town 375 residents by 1890, in addition to a fluctuating population of cowboys, sheepherders, and prospectors from the Book Cliffs and the San Rafael Desert. The town's location on the "outlaw trail" between Robbers Roost and Browns Park also contributed to its "wild west" reputation during that period.
In the early 1890s, the railroad moved much of its divisional operations to Helper, cutting the Green River population by more than half. This boom-and-bust cycle was to be repeated several times in the twentieth century. An oil boom in 1901 brought a rush to locate claims and some drilling activity but no commercial production. In 1906 a land developer named E.T. Merritt began promoting Green River as a fruit-growing area comparable to the Grand Valley of Colorado. Several hundred acres of peach trees were planted on both sides of the river, but problems with the irrigation system and harsh winter temperatures killed most of the trees before they could come into production. The southeastern Utah uranium boom of the 1950s provided a temporary economic stimulus. More important was the establishment of the Utah Launch Complex of the White Sands Missile Base in 1964, which brought the town's population to a high point of almost 2,000 before the closing of the complex in the 1970s led to yet another economic downturn.
Each of these boom cycles had some lasting impact upon the community. The "Farrer Subdivision" that makes up the southeastern portion of the town was a product of the railroad era. The "upper town" to the north and west was developed during the peach boom, a period that also saw the incorporation of the town in 1906 and the building of a high school in 1910. The Community Presbyterian Church was also established during this period. A Latter-day Saint ward was organized in 1904, disbanded in 1915, and reestablished in 1923. During the uranium boom, Jim Hurst developed an innovative flying service to carry workers and supplies to remote mining locations. The successors to Hurst's operation now carry on an active business flying river running parties. The "missile base" era brought new schools and civic services and saw the Community Church become the Green River Bible Church. Catholic and Baptist worship services were also instituted during this period.
Agriculture and ranching have been important to the Green River economy from the beginning. While the climate proved unsuitable for peaches, the relatively long frost-free season and hot summer temperatures of Green River's 4,000-foot elevation are ideal for growing melons. J.H. "Melon" Brown was experimenting with the crop as early as 1900, and the industry reached its peak in the 1920s when the Green River "winter melon," a hard-skinned variety that would keep until Christmas, was well known in Midwestern and Eastern markets. The largest agricultural operation was the Wilson Produce Company, whose properties were later acquired by Thayn Brothers. Melons are still an important crop, and the annual Melon Days celebration is a highlight of the local social year.
Green River's location is still its most important asset. Early attempts to establish commercial riverboat operations between Green River and Moab ended in failure, but pioneer "river rats" like Bert Loper laid the foundation for a recreational boating industry. The town's river heritage is celebrated in the John Wesley Powell River History Museum, opened in 1990. The historic Green River crossing is now the route of Interstate 70. The 105 miles from Salina to Green River represent the longest stretch without services on the entire Interstate highway system, so traveler service industries are quite naturally the town's economic mainstay today. The population of Green River in 1990 was 744 in Emery County plus an additional 122 across the river in Grand County.