North America, Lake Conibaz and Saginaw
"Lake Conibaz and Saginaw. The water of this great lake is fresh and the bounds of it are unknown. Going there by boat, one arrives at the Kingdom of the Saginaw."
The Great Lakes were not charted by Europeans until after Ricci's map, but the fictive Lake Conibaz, which briefly appeared on late 16th-century French and Dutch maps, hints at some knowledge of North America's large interior lakes. Although placed too far to the west, the area described appears to be Michigan.