Donal O’Connell, retired managing director of the D.C. office of ColumbiaNational Real Estate Finance, died Aug. 10 at his home in Bethesda. He was 64.

   The cause was lung cancer, his wife, Katherine Sierra, said.

   Mr. O’Connell retired in 2008 after a 30-year career in commercial real estate finance. From 1992 until retirement, he was with ColumbiaNational. Earlier, he had been an officer at First Union Mortgage and at Randall H. Hagner.

   At his death, Mr. O’Connell was president of the Sumner Citizen’s Association, a neighborhood civic group. In that role, he participated in negotiations that led to a major redesign of the 37-acre campus of the former Defense Mapping Agency in Bethesda.

   Donal Celsus Paul O’Connell was born in Kilkenny, Ireland. He graduated from University College Dublin with a degree in architecture in 1973 and received a master’s degree in city and regional planning at Harvard University in 1978. He emigrated to the United States in 1976 and had lived in the Washington area since 1978.

   Mr. O’Connell was a board member and treasurer of the Little Falls Watershed Alliance and led teams of youths in cleaning up parks and streams to reduce pollution.

   Survivors include his wife of 35 years, Katherine Sierra, a former World Bank vice president, of Bethesda; and two children, Christine O’Connell of Minneapolis and Brian O’Connell of San Francisco.

— Bart Barnes