McHenry was elected as a Democrat to the Forty-second Congress (March 4, 1871 – March 3, 1873).
He resumed the practice of his profession in Hartford.
He served as delegate to the State constitutional convention in 1890.
He died in Hartford, Kentucky, December 17, 1890.
He was interred in Oakwood Cemetery.
The town of McHenry, Kentucky is named in his honor.