Because the area of Northeast Texas encompassing present Bowie County was considered by many to be part of Arkansas, it was the site of some of the earliest white settlement in Texas.
Hunters and traders were active in the area by 1815, and in contiguous Red River County permanent settlement was underway by 1818. Although the details of earliest settlement in Bowie County are not clear, the area was probably settled around 1820, when Miller County, Arkansas, was organized. This county encompassed not only what is now Bowie County, but all of the Red River settlements.
Although the early settlers seem to have regarded the area as part of the United States, when the United States government refused to issue them land titles many of these settlers turned first to the Mexican government and then to Arthur G. Wavell's agent, Benjamin R. Milam, in an attempt to obtain valid land titles. While doing so, they continued to send representatives to the Arkansas legislature. Red River County, which included all the territory now in Bowie County, was established by the Convention of 1836
Bowie County was demarked 12/17/1840 and named for James Bowie. As originally delineated, the county included all or part of the territories of present Cass, Titus, and Morris counties. It was organized in 1841. In 1846 the county was reduced to its present size and boundaries with the establishment of Cass and Titus counties. DeKalb, in the western part of the county, was designated temporary county seat, while a commission was appointed to choose a more appropriate permanent site. The commission chose the town then named Boston, which became the county seat in 1841. In the mid-1880s the citizens of Texarkana conducted a successful campaign to make Texarkana the county seat. About five years later residents of the western and central parts of the county campaigned successfully for yet another county seat, this one to be at the geographic center of the county. The new courthouse was constructed in 1890, and the town that grew up around it was named Boston. -Handbook of Texas Online: Bowie County