Henry Louis Diamond was born in Chattanooga, Tenn., on May 24, 1932, a descendant of Jews from Russia and Poland who paused in their migration for a generation or so in Ireland. His father, Louis, was a shopkeeper. His mother was the former Esther Deich. Mr. Diamond received a bachelor’s degree from Vanderbilt University in 1954, served in the Army and graduated from Georgetown University Law Center. In 1975, Mr. Diamond joined what became Beveridge & Diamond, a Washington law firm that describes itself as the nation’s largest dedicated to environmental and natural resources law. Through the firm, he advised corporations and municipalities and served on dozens of nonprofit boards and commissions. In addition to his wife, the former Elizabeth Tatum, who is known as Betty, he is survived by their daughter, Laura Diamond Decker.