George Robertson Dennis (April 8, 1822 – August 13, 1882), a Democrat, was a United States Senator from Maryland, serving from 1873 to 1879.

[2] He graduated from Rensselaer Polytechnic Institute in Troy, New York.

He entered the University of Virginia at Charlottesville, and studied medicine at the University of Pennsylvania School of Medicine in Philadelphia.

He graduated in 1843 and practiced in Kingston, Maryland, for many years, until later devoting himself to agricultural pursuits.

He died in Kingston in 1882, and is interred in St. Andrew's Churchyard of Princess Anne, Maryland.