From the Baltimore City Landmark plaque at the entrance:
"Green Mount Cemetery was dedicated in 1839 on the site of the former country estate of Robert Oliver. This was at the beginning of the 'rural cemetery movement'; Green Mount was Baltimore's first such rural cemetery and one of the first in the U.S. The movement began both as a response to the health hazard posed by overcrowded church graveyards, and as part of the larger Romantic movement of the mid-1800s, which glorified nature and appealed to emotions.
Green Mount reflects the romanticism of its age, not only by its very existence, but also by its buildings and sculpture. The gate way, designed by Robert Cary Long, Jr., and the hilltop chapel, designed by J. Rudolph Niernsee and J. Crawford Neilson, are Gothic Revival, a romantic style recalling medieval buildings remote in time.
Nearly 65,000 people are buried here, including the poet Syndey Lanier, philanthropists Johns Hopkins and Enoch Pratt, Napoleon Bonaparte's sister-in-law Betsy Patterson, John Wilkes Booth, and numerous military, political and business leaders."