From their website:
Located just off the lobby of the Willard InterContinental Washington, the Round Robin & Scotch Bar has been a lively meeting place for DC’s political and social elite since the days of Abraham Lincoln. Long renowned among the best DC bars, this spot was known as the nexus of “Rum Row” and the “E Street Corridor” -- plying its trade to luminaries such as Mark Twain and Walt Whitman. Today, this fashionable downtown Washington DC bar draws a smart, stylish cross section of DC movers and shakers.