Donald R. McLennan

McLennan served as the Chairman of the Board from 1935 until his death in 1944 in Lake Forest, Illinois.

In 2020, Marsh & McLennan Companies had over 76,000 employees and annual revenues of $17 billion.

In the early 1900s, McLennan established a standard for thorough research in assessing risk: he spent 30 consecutive nights on a sleeper train, traveling coast to coast across the U.S., to inspect the operations of the railroad lines.

By 1917, the year the United States entered World War I, Marsh & McLennan had established offices throughout the country.

For the duration of the war, no U.S. company could build an industrial plant without McLennan's approval.