With the termination of hostilities, Portland was designated flagship of Vice Admiral George D. Murray, Commander Mariana Islands, who was to accept the surrender of the Carolines.
The ship steamed to Truk Atoll and there Murray, acting for Fleet Admiral Chester Nimitz, accepted the formal capitulation of the senior Japanese military and civilian officials in ceremonies aboard Portland.
She was then selected for Operation Magic Carpet duty, and returned to Pearl Harbor from 21–24 September embarking 600 troops for transportation to the United States.
She crossed the Panama Canal on 8 October and arrived at Portland, Maine, for Navy Day celebrations on 27 October.
She then conducted two trans-Atlantic crossings in November and December, bringing troops home from the European Theater.
She reported on 11 March 1946 to the Philadelphia Naval Shipyard for inactivation and assignment to the Reserve Fleet.
She decommissioned at Philadelphia Navy Yard on 12 July 1946 and was maintained in the United States Reserve Fleet.
 While she was identified as one of the few ships that fought through the entire war and not missed any major battle, no attempt was made to save her as a museum ship at either Portland, Maine, or Portland, Oregon.
 She was struck from the Navy List on 1 March 1959 and sold to Union Minerals and Alloys Corp. in New York on 6 October.
She was scrapped at Wainwright Shipyard in Panama City, Florida, during 1961 and 1962.

Her tripod mast was preserved at Fort Allen Park, Portland.
She received 16 battle stars for World War II service, making her among the most decorated US ships of World War II.
With the termination of hostilities, Portland was designated flagship of Vice Admiral George D. Murray, Commander Mariana Islands, who was to accept the surrender of the Carolines. The ship steamed to Truk Atoll and there Murray, acting for Fleet Admiral Chester Nimitz, accepted the formal capitulation of the senior Japanese military and civilian officials in ceremonies aboard Portland. She was then selected for Operation Magic Carpet duty, and returned to Pearl Harbor from 21–24 September embarking 600 troops for transportation to the United States. She crossed the Panama Canal on 8 October and arrived at Portland, Maine, for Navy Day celebrations on 27 October. She then conducted two trans-Atlantic crossings in November and December, bringing troops home from the European Theater. She reported on 11 March 1946 to the Philadelphia Naval Shipyard for inactivation and assignment to the Reserve Fleet. She decommissioned at Philadelphia Navy Yard on 12 July 1946 and was maintained in the United States Reserve Fleet.  While she was identified as one of the few ships that fought through the entire war and not missed any major battle, no attempt was made to save her as a museum ship at either Portland, Maine, or Portland, Oregon.  She was struck from the Navy List on 1 March 1959 and sold to Union Minerals and Alloys Corp. in New York on 6 October. She was scrapped at Wainwright Shipyard in Panama City, Florida, during 1961 and 1962.
Her tripod mast was preserved at Fort Allen Park, Portland. She received 16 battle stars for World War II service, making her among the most decorated US ships of World War II.
USS Portland (CA-33)