Candle-light vigils to remember her life were held throughout the country.
Hundreds of people in her hometown also gathered to remember Grace.
Before he left the country, David Millane thanked the people of New Zealand for their outpouring of love, numerous messages, tributes and compassion.
"Grace was not born here and only managed to stay a few weeks, but you have taken her to your hearts and in some small way she will forever be a Kiwi," he said in a statement.