This is one of Wyoming's many roadside monuments that's not longer really road side.
This monument is on the old highway that ran from Orin Junction to Wheatland. When the Interstate was built, Orin Junction was bypassed and for that matter, the Interstate zips through, not into, Wheatland. Many such monuments exist, a few of which are now completely marooned.
This one commemorates Jim Bridger's ferry across the North Platte River, which was placed in 1864.
A Burlington Norther Railroad Bridge, which itself isn't youthful, very near where the ferry once was.