In short, the Mormon leaders wanted to find a 'short cut' between their established settlements in western Utah and new ones in south eastern Utah. They already had northern and southern routes (in green), but were having trouble with those. Thus they blazed the new trail (in red.)
In the visitors center were an excellent film about the trip and local volunteers who had ancestral ties to the event. The trip began in fall of 1879 and was supposed to take six weeks. Six months later they reached their destination!
Although the whole route was difficult, the worst section was at Hole-in-the-Rock where the pioneers had to navigate a cleft in the cliffs down to the Colorado River. It took six weeks to widen this mile-long notch enough to allow the wagons access.
Photo taken in 1950 by Harold Monson, Deseret News photographer.
It's truly unbelievable to me that no lives were lost.
The above two artist's renderings were taken off the information boards outside the visitors center. The last one has a fascinating story to go with it.
Not only did they not lose anybody on the trip, but two babies were born along the way.
I can't stay serious for long. Does anybody know the name of these lovely trees?