The trail follows the Platte River and North Platte River through Nebraska and Eastern Wyoming. Here near present-day Casper it would cross the river one last time, then leave it behind for good. At first the usual "last crossing" was upstream from Casper a few miles at Bessemer Bend. But in 1847 Brigham Young left a small contingent from his lead party of Mormon pioneers to establish a toll ferry across the river. The line to use the "Mormon ferry" over the next several summers was sometimes days long, and the ferry raised funds that were much-needed in supporting the Mormon migration. Fort Casper would later grow up around the site of this ferry.