Mosier Valley was established in the 1870s on the north bank of the Trinity River just south of the sites of Hurst, Euless, and Bedford in Tarrant County. It was founded by Robert and Dilsie Johnson and ten other emancipated slave families, most of whom had been taken from Tennessee through Missouri to the J. K. or T. W. Mosier plantation. Trinity bottomland was given and sold to the freedmen by the Mosier and Lee plantation families, and the African Americans established a close-knit farming community. They raised cotton and corn as cash crops, maintained vegetable gardens, and kept farm animals. Many also worked as handymen, sharecroppers, and nannies for residents in the Hurst, Euless, and Bedford area. The Oak Grove Baptist Church was founded in the community in 1874 and an elementary school in 1883. The Mosier Valley school was always in one of the Hurst, Euless, or Bedford school districts, but the Black community was allowed to elect a trustee from 1884 to 1904. John Calhoun Parker established a widely patronized syrup mill around 1900. Also around that time the community constructed a building that was shared by the school, the church, and the Masonic lodge. The congregation changed its name to St. John Missionary Baptist Church and built its own building in 1911, on the same site the church occupied in the 1990s.
The heyday of Mosier Valley was from about 1910 through the 1930s. During this time it reached its population peak of perhaps 300, and had lively string bands, square dances, church revivals, and public festivals. Whites attended some events, though most of the racial mingling involved Black and White males shooting dice and betting on cockfights. In August 1949 Euless school superintendent O. B. Powell attempted to transfer forty-six local Black students to "colored" schools in Fort Worth, since busing them would be cheaper than maintaining the ramshackle Mosier Valley facility. Mosier Valley parents, with help from the National Association for the Advancement of Colored People, had the district enjoined. United States District Judge Joe Dooley observed in 1950 that Texas laws specified that students had a right to be educated in their own districts and that a district's schools were supposed to be funded on an equal basis. On September 4, 1950, Mosier Valley parents and thirty-five grade-school students entered the Euless school and tried to enroll. A crowd of some 150 Whites gathered outside, harassed photographers, and jeered as the Blacks later filed out. Powell had informed the Blacks that state segregation laws took precedence over all others. Segregation lingered, served by a new Mosier Valley school (1953–1968), but under federal duress in 1968 the Mosier Valley school closed and the Euless district was fully integrated. In 1983 the Texas Historical Commission placed a marker at the site of the old Mosier Valley school on Mosier Valley Road.
The anticipated construction of what is now the Dallas-Fort Worth International Airport in 1960 caused Fort Worth to extend its boundaries to the east (to reach the site) in a strip of land that included Mosier Valley. In the early 1990s the remaining 150 or so residents of Mosier Valley were surrounded by gravel pits and machine shops, and many families still relied on well water and septic tanks. In 1994 Trinity Boulevard, a six-lane, fully accessible highway, was planned to pass through Mosier Valley, then a residential community within Fort Worth.