Elrond Peredhil is the elven Lord of Rivendell, the keeper of the Last Homely House.  He first appears in Chapter Three, "A Short Rest:"

"In those days of our tale there were still some people who had both elves and heroes of the North for ancestors, and Elrond the master of the house was their chief." (Chapter 3). 

As the master and lord of Rivendell, Elrond is both wise and kind, accepting the weary travelers into his realm for some much needed rest.  Tolkien characterizes Elrond as being both "wise as a wizard" and "venerable as a king of dwarves" (Chapter 3).  Although Elrond does not make much of an appearance in The Hobbit as he does in Lord of the Rings, he does provide critical information to the dwarves' quest to reclaim the Lonely Mountain.  Elrond relays the information about Gandalf, Thorin, and Bilbo's elvish blades as well as helping the dwarves to interpret their map of the Lonely Mountain which was inscribed with moon-letters.