Dear 100 Hour Board,
In the continental United States, what is the furthest in miles you can be from a temple and where is it?
Dear my synesthesia thinks Emma is a beautiful name (mostly deep green),
Did you know that I love questions like this?
I love questions like this.
Luckily for you, I had already collected most of the data that I needed in Board Question #70656. I updated the data to include the five temples announced since then, and then selected from that group all temples in the US. I also included several temples in Canada and Mexico; as you'll see in my maps, some parts of the United States are closer to temples in Mexico or Canada than temples in the US. Before actually researching the answer to your question, I created Thiessen polygons around each temple. The area inside of a Thiessen polygon is closer to the temple at the center of the polygon than it is to any other temple I've included on the map.
This map doesn't answer your question, though—it can tell you which temple is closest to each point, but not which point is furthest from a temple. For that, I turned to buffers. I started with a buffer at 200 miles, then added another buffer at 250 miles and a third at 300 miles. You can see the output below. I colored all distances under 200 miles from a temple in lime green, distances 200-250 miles from a temple in green, and distances 250-300 miles from a temple in aqua. All distances over 300 miles were left in white.
For your convenience, I created another map, zoomed in on the peninsula.
All of the area in Michigan shown in white on this map is between 300 and 325 miles from a temple. I did some investigation on Google Maps, and for the most part it looks thoroughly uninhabited, including quite a bit of land protected in state and national parks/forests/lakeshores. The only city that Google deemed worthy of showing is Munising, population 2,355. From a bit of browsing on Wikipedia, it looks like there are a few other communities in the area with populations ranging from the low hundreds to just over 1,000, but nothing much larger.
There is a ward in Marquette, just inside the 300-mile mark, but there are no wards or branches in the white area on the map.
There you have it!