To translate "Where is the door?" into Spanish, you can use the phrase "¿Dónde está la puerta?" The word "dónde" means "where," "está" means "is," and "la puerta" means "the door." It is important to note that in Spanish, we use the verb "estar" to indicate the location of an object.
The correct translation is: "¿Dónde está la puerta?"