Not all members of the black frontier regiments fit specifically into a certain racial category. For decades prior to the late 19th century, people from different countries had immigrated or were brought to the United States. They represented many varying ethnic groups beyond those who were of African or European descent. For all of them, the one common opportunity for employment was the United States military. The 19th century army followed an unofficial policy that those who were other than white, and had a fair complexion, could be placed in white units. Conversely, the military relegated individuals with a dark complexion to the segregated units. People from areas of the world like Latin America, the Caribbean, the Middle East, and the Philippines might find themselves in this dilemma. Additionally, men of mixed African and European  descent., or those considered "mulatto", might find themselves in either unit depending on complexion. This impacted Private Samuel W. Brown, who served in a white regiment. It was discovered that he had mixed ethnicity and his African ancestry categorized him as Black. Eventually, the man’s commanding officer, Captain John Bigelow, requested the private’s dismissal for “enlisting under false pretenses.” 

Seminole Scouts

These Black scouts descended from runaway slaves who settled with Seminole Indians in Florida. Along with the Seminole peoples, In the 1830s, the U.S. government forced them to relocate to Indian Territory (Oklahoma). By 1870, the United States Army began recruiting some of them as scouts due to their knowledge of the Texas terrain. Originally commanded by Lt. John L. Bullis (white officer of the 24th Infantry), and numbering no more than fifty men, they served with distinction during the 19th century. They engaged in 26 campaigns, often heavily outnumbered. A small group served through the early 20th century at Fort Clark, Texas and later many would enlist in the regiments of Black regulars. In 1914, the army officially disbanded the detachment.