The world has flooded Hallee Sorenson with thousands of cards and gifts for her 19th birthday.

When no one showed up to her 18th birthday party last year, Hallee Sorenson was heartbroken.



The US teen, who has autism, had been waiting anxiously to bond with classmates, but "not a single one" made it to her celebration, leaving her family shattered.



So Sorenson's cousin knew she had to do something this year to make things right.



Rebecca Guildford shared the photo of Sorenson sitting alone surrounded by balloons, and appealed to the world to "flood her mailbox" with birthday cards.



They have come through.

READ MORE: US family plans big birthday bash for teen with autism

Postal officers in Bangor, Maine, have delivered more than 10,000 cards, letters and parcels to the Sorenson household since Guildford made the Facebook post on June 8.

There has been so much mail, they had to be bundled in crates and transported in trucks.

Some of the gifts include a parcel from a soldier stationed in Afghanistan, a message from the state of Ohio, and a doll from a NASA employee.

Hallee's 19th Birthday/Facebook The postmaster from Bangor, Maine, unloading all of Hallee's mail from the truck.

A family which was en route to Louisiana also stopped by the house to give Sorenson a card and balloon.

A Facebook page dedicated to sharing updates on Sorenson's 19th birthday shows the teen happily posing with her many presents this year.

More mail is expected to flood in ahead of her birthday, which falls on July 2.

Sorenson's overwhelmed mother Allyson wrote: "You rock so hard. My heart is fit to burst."

Her aunt Robyn thanked well-wishers for their kind thoughts, saying: "Our gratitude is hard to put into words.

"This is all reaffirming that most people are kind and loving, and that we all have the capacity for caring about others, even if they're many miles away.

"We're all extended family."