The Charles Hall Ferry is a ferry operating in the state of Utah. It crosses Lake Powell, a reservoir on the Colorado River, formed by the Glen Canyon Dam. The ferry carries automobiles and passengers, with a maximum occupancy of 22 vehicles and 150 passengers. The ferry connects the two communities of Bullfrog and Hall's Crossing. (Although the ferry currently operates on the lake, it was the site of an earlier ferry in pioneer days, on the undammed Colorado River). The two towns are only three miles apart, but without the ferry, it would take over 120 miles of travel across somewhat difficult roads to connect them.
Both of the communities connected by this ferry are resort communities with few year-round residents. This is a sparsely inhabited corner of Utah, and the ferry is not carrying that many regular commuters. However, because of the many tourists that come into the region, it still handles a lot of traffic: an article from 2006 says that it handles around 12,000 vehicles and 250,000 passengers a year. The ferry is itself somewhat of a tourist attraction, with its half hour, 3 mile journey from north to south giving an excellent view of the lake and surrounding terrain.
To me, it is also a fascinating example of something being found in an unexpected place. The level of the lake is between 3600 and 3700 feet, meaning that this ferry is probably the highest altitude ferry in the United States, and one of the higher ones in the world. Although a ferry in the middle of the mountains in one of the driest areas of the country might be unexpected, it is indeed there.
https://www.udot.utah.gov/main/f?p=100:pg:0:::1:T,V:2257,
https://www.lake-powell-country.com/lake-powell-ferries.html
https://www.deseretnews.com/article/705279908/UDOTs-ferry-on-Lake-Powell-is-no-desert-mirage.html