What date did the Manhattan Project end?

The Manhattan Project is generally considered to have ended with the successful testing of the atomic bomb on July 16, 1945, in the Trinity Test in New Mexico. However, the official conclusion of the project is often marked by the end of World War II, following the bombings of Hiroshima on August 6 and Nagasaki on August 9, 1945. After the war, the project was officially disbanded in 1946.