The director gave the keynote speech at the Soldiers' National Cemetery in Gettysburg to mark the 149th anniversary of Lincoln's three-minute talk, delivered in 1863 after the Union troops defeated the Confederacy.
Spielberg, whose latest film Lincoln centres around the 16th U.S. President, admitted he felt "humbled" to stand near the site where the leader gave his famous oration.
He told the crowd, "The reason for this concentration of heartbreak and heroism in a geographical location is simple, and Lincoln told us what it was that day, when he found his best and his truest voice: It's the courage, the selflessness, the strength, endurance, heroism and the sacrifice of the patriots who are buried here - most of them terribly young men; men no older than my three sons. It's the memory of those honoured dead, those in their graves, and those who have never been found, that brings all of America, always, back to Gettysburg."
The filmmaker also thanked the historians in attendance whose research helped him make Lincoln, which stars Daniel Day-Lewis in the title role.
He added, "Like most people who've spent a lot of time thinking about Abraham Lincoln, he has come to feel like one of my oldest and one of my dearest friends. I imagine I'm talking to many people who feel the same way. I'm luckier in one sense than nearly all of you, in one sense - I have Daniel Day-Lewis' phone number in my speed dial. And if I start to really miss him terribly, I can just call him up and ask him to tell me a story. I haven't done this. I have no idea what Daniel would think of me if I did. He would probably change his number, and that's certainly what Lincoln would have done if he had a cell phone."