Henry W. Keyes (May 23, 1863-June 19, 1938) was an American farmer, banker, and Republican politician from Haverhill, New Hampshire. Born in 1863 in Newbury, Vermont, he served in both houses of the New Hampshire state legislature before being elected Governor in 1916, and later served eighteen years in the United States Senate.
When Keyes was sworn in as a U.S. Senator on March 4, 1919, he still had three months to go on his term as Governor. He was the first politician in over a hundred years to hold both offices at the same time. He died in 1938 in North Haverhill, New Hampshire, and is buried at the Oxbow Cemetery in Newbury, Vermont.