What makes us great. Founded in 1972 by four graduates from the University of Tulsa College of Law, Riggs Abney is one of Oklahoma’s largest law firms. Riggs, Abney, Neal & Turpen, merged with the firm Robinson, Lewis, Orbison, Smith and Coyle in 1994 to become Riggs, Abney, Neal, Turpen, Orbison & Lewis. Today, the firm is known simply as Riggs Abney, with offices in Tulsa, Oklahoma City and Colorado, providing broad based legal counsel and representation in all aspects of law.