It spread across sub-saharan Africa since the 8th century onwards, where Islam is the majority or significant minority religion in many modern countries.
The states that Islam was able to spread through and begin to influence were in West Africa (including places like Senegal, Gambia, Niger, Guinea, Burkina Faso, Mali, and Nigeria).
Because of facts like this, claims can be made that this is how Islam first got the Americans and how it was able to grow and infiltrate its practices and ideas into other slaves who may not have come from those same western African countries.
These slaves continued to practice and preach their traditions and ways of life and pass them on to their friends and families growing the culture and religion.
These same Lowcountry articles continue to go on and talk about how Americans today only picture middle eastern people and even the violent terrorist groups that come from some of those counties when thinking about Islam.