From the Overview: "Nigeria is Africa's most populous country, largest economy, and leading oil producer. Successive U.S. Administrations have described the U.S.-Nigeria relationship as among the most important in sub-Saharan Africa: the country is the United States' second-largest trading partner and third-largest destination for U.S. foreign direct investment in the region, and it routinely ranks among the top annual recipients of U.S. foreign aid globally. Nigeria plays a major political and economic role in Africa and wields influence regionally. Nigerians make up the largest African-born population in the United States, generating billions of dollars in annual remittance outflows."
CRS Report for Congress, RL33964
Congressional Research Service: https://crsreports.congress.gov/