Você ficará dois dias no país, então não é um trânsito. Você está saindo do aeroporto (suponho que não vai ficar dois dias no aeroporto!) E visitando os EUA.
Do nationals or citizens of countries that participate in the Visa Waiver Program require travel authorization if they are only transiting the United States en route to another country?
Eligible nationals or citizens of countries that participate in the Visa Waiver Program require either a travel authorization or a visa to transit the United States. If a traveler is only planning to transit through the United States en route to another country, when he or she completes the travel authorization application in ESTA, the traveler should select "Yes" to the question "Is your travel to the US occurring in transit to another country?".