By late 1944, the locus of the Manhattan Project had shifted to the Los Alamos Laboratory in New Mexico, and Allison went there in November 1944 as the chairman of the Technical and Scheduling Committee. He was able to inform Groves in March 1945 that an implosion-type nuclear weapon would be ready for testing in July. Allison formed part of the "Cowpuncher Committee" that "rode herd" on the implosion project, ensuring that it stayed on track and on schedule. Fittingly, he was the one who read the countdown over the loudspeakers at the Trinity nuclear test in July 1945. Groves presented Allison with the Medal for Merit for his work on the Manhattan Project in a ceremony at the University of Chicago on January 12, 1946.