In north america, where is population density the highest?

In terms of individual states, the answer would be New Jersey. Otherwise, the REGION that is most densely populated is the east coast, specifically the Northeastern part of the U.S.

Hope this helps!

ń, wǒ shuō yīngyǔ, dàn wǒ huì shuō qítā yǔyán, rú xībānyá yǔ fǎyǔ yìdàlì yǔ hé pǔtōnghuà, suǒyǐ bùyào pànduàn, dànshì