There was a flyover of jets in his hometown, and 100 people became US citizens at a naturalisation ceremony in his honour.
Jimmy Carter celebrates his 100th birthday on Tuesday, making him the first US president to reach the milestone.
Carter, a Democrat who served in the White House from 1977 to 1981, has spent the past 19 months in hospice care in his home state of Georgia.
But the former peanut farmer, who first entered politics in the 1960s as a state senator, is "emotionally engaged and still having experiences and laughing, loving," his grandson, Jason, said in September.
And the centenarian still has political ambitions: "I'm only trying to make it to vote for Kamala Harris" in November's election, the humanitarian and Nobel Prize recipient said, according to his grandson.
He was the best president we have had since I was alive. He has integrity. He sold his family farm to avoid conflict of interest when running for office. He built houses for decades after leaving office for the needy.
That was just a bad ordering of words in that sentence. He failed to get re-elected and then a few years later he and his wife started building houses for the needy.