Father Millet Cross and East Gun Tower [or "North Redoubt"] at Fort Niagara in Youngstown, Niagara County, New York, USA.
Photo: J. Carl Burke, Jr. - Historic American Buildings Survey—HABS, October 1967
Public Domain
https://commons.wikimedia.org/wiki/File%3AFather-Millet-Cross-01.jpg
Established by Presidential Proclamation: September 5, 1925 by President Calvin Coolidge
Abolished as a National Monument: September 7, 1949 by the 81st Congress
Wikipedia:
https://en.wikipedia.org/wiki/Father_Millet_Cross
Originally managed by the War Department, the monument was transferred to the National Park Service by President Franklin Roosevelt's Executive Order 6166 on June 10, 1933. It was transferred to the State of New York in 1949 and is now a part of Old Fort Niagara State Park.
According to National Parks Traveler:
When the Army declared Fort Niagara surplus in 1945 (it wasn’t completely demilitarized until 1963), plans were made to abolish the national monument and turn the property over to the state of New York. This was done on September 7, 1949, when Congress transferred the Father Millet Cross National Monument to the state of New York for public use.
How small was it? It was just the cross itself, apparently... "A tennis doubles court is a little over 2,800 square feet, which is nearly nine times the size of the former Father Millet Cross National Monument. "
National Parks Traveler