The letters were written by Mr Obama between 1982 and 1984 after moving to New York from California, where Ms McNear remained a student.
Interestingly, the letters actually document the gradual decline of their long-distance relationship.
"I trust you know that I miss you, that my concern for you is as wide as the air, my confidence in you as deep as the sea, my love rich and plentiful, Love, Barack," Mr Obama writes in the first letter.
In another letter, Mr Obama writes how much he enjoys his relationship with Ms McNear.
The challenge, he writes, "lies in forging a unity, mixing it up, constructing the truth to be found between the seams of individual lives. All of which requires breaking some sweat. Like a good basketball game. Or a fine dance. Or making love."
"We will talk long and deep, Alex," he adds, "and see what we can make of this."
In a later letter, he reminisces about the time the two spent together.
"A young black man with his arm behind his head, staring at the ceiling with moist eyes, and a young white woman resting her head on his arm, alone and facing the swirling expanse, outside the room, inside themselves, separate in the eye of the storm," he writes.
"I think of you often, though I stay confused about my feelings," Mr Obama writes. "It seems we will ever want what we cannot have; that's what binds us; that's what keeps us apart."
In one of the final letters, Mr Obama acknowledges how much he appreciates Ms McNear's enduring friendship even as their romantic relationship fades.
"When I sit down to write, I no longer feel the need to bleed for brilliance on the page; I trust the strength of our relationship enough that I can show myself with curlers in my hair, my will sapped, my confidence shaken, a bit peevish perhaps, a bit dull," he writes.
The letters are, unsurprisingly, making the Internet swoon.
"The Barack Obama love letters that were released are completely melting my heart right now," tweets one person. "These make me love our former President Barack Obama even more. Such beautiful writing, imagery and love," tweets another.
"1. Obama has lovely penmanship 2. These excerpts are eloquent 3. How mortifying to have old love letters published," jokes a third. Click for more trending news