The US women's soccer team member received the key during last week's victory celebration at City Hall.
But someone stole it from her hotel room in Los Angeles days later along with jewelry, money and other items.
New York City First Lady Chirlane McCray personally handed a replacement key to Long Tuesday night.
Long's room at the Ritz-Carlton hotel was burglarized when she and her husband left the room and the door was left ajar. The couple realized the items were missing Thursday.
There was no sign of forced entry into the room because the door was ajar.
"After the @ESPYS show someone stole my wedding ring, cash and the key to my favorite city after just receiving it from my hotel room. Do you make copies @NYCMayor ? I would love a new one," Long tweeted late Thursday.
Bill de Blasio replied: "Like any good New Yorker, we keep a spare for our neighbors! We got you covered."
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