The accurate term for this population is Roma (or Romany). There is no official census in the United States that tracks ethnicity based on Roma identity. Therefore, it's impossible to definitively say which state has the "highest" Roma population.
However, some estimations suggest that large Roma communities exist in:
* Pennsylvania: There are historically established Roma communities in Pennsylvania, particularly in the Pittsburgh area.
* New Jersey: Some reports mention a significant Roma population in New Jersey, though specific numbers are not readily available.
* New York: The New York City area is believed to have a substantial Roma presence.
* Ohio: There are reports of communities with Roma heritage in Ohio.
It's crucial to remember that these are just estimates, and there is no comprehensive data available on the Roma population in the United States.