Which west African empire existed for the longest amount of time?

The Ghana Empire is considered the longest-lasting West African empire, with its origins tracing back to around the 6th century and lasting until the 13th century. It was known for its wealth derived from trade, particularly in gold and salt. The empire played a crucial role in trans-Saharan trade and laid the groundwork for subsequent empires like the Mali and Songhai. Its longevity and influence significantly shaped the history and culture of the region.