When the sun is below the horizon for more than 24 hours, this is known as a polar night. Each of the poles on Earth, one in the North and one in the South, experience polar nights across approximately two months each year. During polar nights, while it is day in the Arctic Circle, it would be night in the Antarctic circle as well as the opposite being true.
In the USA, there's no need to be worried about polar nights unless you live on the northern most territories of Alaska. There, in towns such as Barrow which are north of the Arctic Circle, residents will experience constant state of night / twilight from November 18th to January 23rd.
While this type of day cycle may appeal to vampires or other nocturnal creatures, it certainly is not too ideal for the average person as temperatures sink to as low as -20 degrees Fahrenheit due to lack of sunlight.
Although it seems like such an alien concept, the fact is that during certain times of the year there are places in the world that experience no daylight during polar nights and no moonlight during polar days.