The term refers to the often deadly circumstances that greeted white Westerners who ventured into the regions of Sierra Leone and other parts of Western Africa. "White man's grave" generally concerns the deaths that were brought upon by poor sanitation, disease and the extremes of the tropical climate. Colonists and missionaries were hit hardest. According to one source, the term was coined in reference to Sierra Leone, the first British West African colony. After the British abolishment of slavery in 1772, Sierra Leone was created as a home for freed slaves, and it was described as a
"comfortable establishment in a most pleasant and fertile climate." It was a virtual paradise...
Missionaries and colonists found out the hard way that this was not true. Newly relocated slaves also died in high numbers. Malaria and yellow fever proved to be the main causes.