The two were abducted at gunpoint while on a game drive on Tuesday evening, the Ugandan Tourism Board and Ugandan police said in a statement.
It remains unclear if a ransom was paid in the case of Endicott, who is from Costa Mesa, California, where she has a small skin care shop. The captures had demanded a $500,000 ransom, but it was not immediately clear how much of that was paid or by who.
Authorities gave no more details. Inset is the tour guide Jean Paul.
Heat's Wade will try therapy to ease into retirement
Considering their schedule, that's probably going to be easier said than done. Especially in the beginning, I want to see what I can be great at.
Police said the incident occurred between 6pm and 7pm, along the Edward track, a section located between Katoke gate and wilderness camp.
Four other people were taken at the same time, but they were freed while Endicott and her driver were taken from the park, officials said.
After playing golf on Sunday, Donald Trump tweeted: "Pleased to report that the American tourist and tour guide that were abducted in Uganda have been released".
Jean-Paul Delevoye attend "des clarifications" de la part du gouvernement — Retraites
Dans ses propositions post-"grand débat national", La République en marche propose de réindexer les petites retraites sur l'inflation.
Queen Elizabeth park is about 150 kilometres (90 miles) north of Bwindi Impenetrable National Park, famous for gorilla trekking.
Kidnappings in Uganda's protected areas are rare. The abductors had been using Endicott's phone to negotiate her release and were in contact with authorities almost everyday, officials said.
They were traveling in a motor vehicle Reg No UAR 777E of World Frontiers Safaris Uganda with an elderly couple, also tourists. It borders the famous Virunga national park, the oldest in Africa.
Browns sign ex-AAF QB Gilbert, FA safety Burnett
In his eight seasons in Green Bay, Burnett broke up 44 passes, snagged nine interceptions and recorded 2016 tackles. He made 30 tackles over 11 games last season after spending the first eight years of his career in Green Bay.