Well, it's that time of the year when the sun is setting earlier and earlier. Yes, the winter solstice is quickly approaching. Although December 22 will mark the shortest day of the year, it's noteworthy that sunset times are not always the earliest on this day.
First, here's the time zones of the United States...
Within the eastern time zone, Maine is the place to look at for the earliest sunsets.
Just as the sunset times may actually be later after the summer solstice, the earliest sunset times may actually occur well before the winter solstice, depending on where you are.
For example, Caribou's earliest sunset will occur on December 9 at 3:43pm. The sun will set at this time through December 14.
One of the earliest sunset times I could find in Maine occurs in Van Buren at 3:42pm, starting on December 7 through the 16th. I provided a partial listing of their sunset times during December below...
I found some honorable mentions in the Pacific Time Zone. Moyle Springs and Copeland ID share the earliest sunset time of 3:48pm right around December 12.