How far can a hobbit walk in a day?

In constructing his lengthy saga, Tolkien freely borrowed from both experience and scholarship…Tolkien used technical points of reference from our world and applied them to Middle-earth. For example, the cycles of the moon in The Lord of the Rings are from the 1942 calendar. And when Tolkien had his characters walk or travel over any great distance, he actually used a British Army ordnance survey manual to find out precisely how far soldiers could move on forced marches.

—Daniel Grotta, J.R.R. Tolkien: Architect of Middle-Earth