Mr. Elkins was a saloon owner during nineteenth century.
According to Judge Tye Mortimer, Elkins has been living in Sunrise, Wyoming, for a very long time, long enough to know the whereabouts of Samuel Colt. Sam and Dean Winchester, in search for Samuel, visit Mr. Elkins' saloon.
Elkins greets them by offering to get them a drink, so Dean randomly orders whiskey. Sam asks if he knows where Samuel Colt is, and Elkins mentions Samuel having past through town about four years ago, currently building a railroad twenty miles outside the city.
Dean later visits the saloon in search of the Sheriff, while Elkins remarks on his new hat. They are disrupted when a man cries, declaring the Sheriff is dead as he stares at a pile of ash and bones. When Dean asks who is going to be the new sheriff, Elkins puts the dead Sheriff's badge on Dean and tells him "congratulations".
Presumably, after Sam and Dean are yanked back into the future by Castiel, Elkins retrieves The Colt they dropped and keeps it as a family heirloom, passing it down eventually to his descendant, Daniel Elkins.