Admiral Adama states that "they are a million light years away from the colonies". Yet, at a distance of one million light years from Earth in any direction there are no stars or galaxies. The next galaxy (Andromeda) would be 2.5 million light years away and the Milky Way itself is only 100,000 light years in diameter. That being said, Adama could have simply been using an inexact phrase to illustrate that they were far from home.
As the camera pans up over Adama sitting by Laura's grave a small, low to the ground fence can be seen behind him. The area is supposed to be undeveloped and uninhabited.
As the deployment of the fleet's population is planed out on Earth's map, the map shown is of Earth today, not as it would have been at a time of pre-language humans. A visible example is of Tasmania's disconnection from Australia, which occurred only 10,000 years ago.
The events of the finale were supposed to have taken place 150,000 years ago. Therefore, when Galactica jumped to our Earth after rescuing Hera, shots of the African continent from space should have shown the Sahara to be lush and green rather than the pale desert it is today.
The final scene is stated to take place on the streets of modern day New York City but in the final shot, the Canadian-style "do not enter" sign and the transit bus in TransLink livery reveals it was actually Vancouver BC.
They're supposed to be in Africa, yet near the end when Admiral Adama and the President get in the Raptor they're situated in front of a stand of paper birch. These are trees found only in North America.