All of the cases have been detected "within gay, bisexual men and other men who have sex with men," Walensky said.
The list of affected states includes Massachusetts, Florida, Utah, Washington, California, Virginia and New York.
Walensky warned that the infection may affect all territories and all groups of the population.
"While some groups may have a greater chance of exposure right now, infectious diseases do not care about state or international borders. They're not contained within social networks and the risk of exposure is not limited to any one particular group," she said.
Monkeypox is a rare viral disease that is usually transmitted to people from wild animals and is endemic in some African countries. Monkeypox can be transmitted through bodily fluids, respiratory droplets and other contaminated materials. The disease usually results in fever, rash and swollen lymph nodes.