The release came after a ransom was paid and a negotiated handover was conducted.
"Security services have this evening managed to rescue" Endicott and her driver Jean Paul Mirenge, the Ugandan government said in a statement. The two kidnap victims returned to a lodge at Queen Elizabeth National Park on Sunday, according to a spokesperson for Wild Frontiers Uganda.
The amount of ransom that was paid and other details of Endicott's release were not immediately disclosed, including the identity of the person or entity that made the payment. The captors had demanded $500,000.
President Donald Trump tweeted about the release Sunday afternoon.
"Pleased to report that the American tourist and tour guide that were abducted in Uganda have been released," he said in the tweet. "God bless them and their families."
Ugandan security forces launched a search for Endicott and the local driver after they were abducted in the wildlife park on April 2. They were ambushed by four gunmen in the park, a protected area near the porous border with Congo, according to Ugandan police and a government spokesman.