See The Nigerian States The US Has Declared Unsafe

The State Department of the United States has declared 20 states in Nigeria as unsafe for its citizens to visit.
It described the security in the affected states as ”fluid and unpredictable”.
The State Department which placed a travel warning on its website on Wednesday and Top on the list of states that Americans should not visit are Adamawa, Borno, and Yobe.
 It said the ability to provide assistance to US citizens in the three states remains severely limited. It charged American nationals in Nigeria to place a premium on their personal security and make personal safety a priority in planning their travels.
The State Department said that except for necessity, travel to 17 other states should be controlled because of kidnappings, robberies, and other armed attacks.
The states are Bauchi, Bayelsa, Delta, Edo, Gombe, Imo, Jigawa, Kaduna, Kano, Katsina, Kebbi, Kogi, Niger, Plateau, Rivers, Sokoto, and Zamfara.
Based on safety and security risk assessments, the Embassy maintains restrictions for travel by US officials to the states listed above; officials must receive advance clearance by the US Mission for any travel to those states”, it stated.
The American Government further advised its citizens to be particularly vigilant around government security facilities like churches, mosques, and other places of worship; locations where large crowds may gather, such as hotels, clubs, bars, restaurants, markets, shopping malls; and other areas frequented by expatriates and foreign travellers.