That announcement made in Ivory Coast - the second stop of his tour to a region where insecurity linked to jihadist insurgencies has increased in recent years.
Blinken arrived from Cape Verde to the Ivorian financial capital Abidjan on Monday (January 22) evening where he watched Ivory Coast play Equatorial Guinea in the Africa Cup of Nations.
On Tuesday, he met with President Alassane Ouattara and later the president of the African Development Bank, Akinwumi Adesina at a rice research institute.
Ivory Coast is one of several West African countries affected by insurgencies that took root in Mali in 2012.
They've spread across the Sahel despite costly, internationally-backed efforts at containment.
Tuesday's funding announcement supplements $300 million the U.S. has already invested in coastal West Africa over the past two years.
The last two destinations for Blinken's trip are Nigeria and Angola.
Key topics being discussed include the fallout of a coup in Niger last year, and Russia's growing influence in the region.
