Were there people living outside of Eden?
Adam and Eve were the only two people upon earth, at first, and they are the only two specifically mentioned as being in the Garden of Eden. Genesis 2:8 says, “And the LORD God planted a garden eastward in Eden; and there he put the man whom he had formed.” Genesis 2:18 says, “And the LORD God said, It is not good that the man should be alone; I will make him an help meet for him.” Genesis 2:22 says, “And the rib, which the LORD God had taken from man, made he a woman, and brought her unto the man.”
With that setting, we then go into chapter 3, to see Eve, and then Adam, fall into sin. Genesis 3:1-7 says, “1 Now the serpent was more subtil than any beast of the field which the LORD God had made. And he said unto the woman, Yea, hath God said, Ye shall not eat of every tree of the garden? 2 And the woman said unto the serpent, We may eat of the fruit of the trees of the garden: 3 But of the fruit of the tree which is in the midst of the garden, God hath said, Ye shall not eat of it, neither shall ye touch it, lest ye die. 4 And the serpent said unto the woman, Ye shall not surely die: 5 For God doth know that in the day ye eat thereof, then your eyes shall be opened, and ye shall be as gods, knowing good and evil. 6 And when the woman saw that the tree was good for food, and that it was pleasant to the eyes, and a tree to be desired to make one wise, she took of the fruit thereof, and did eat, and gave also unto her husband with her; and he did eat. 7 And the eyes of them both were opened, and they knew that they were naked; and they sewed fig leaves together, and made themselves aprons.”
We then see Adam and Eve hiding from God, and there is no mention of any children with them. Genesis 3:8 says, “And they heard the voice of the LORD God walking in the garden in the cool of the day: and Adam and his wife hid themselves from the presence of the LORD God amongst the trees of the garden.” Adam and Eve give their excuses for falling into sin – Adam blames Eve, and Eve blames the serpent. Genesis 3:9-13 says, “9 And the LORD God called unto Adam, and said unto him, Where art thou? 10 And he said, I heard thy voice in the garden, and I was afraid, because I was naked; and I hid myself. 11 And he said, Who told thee that thou wast naked? Hast thou eaten of the tree, whereof I commanded thee that thou shouldest not eat? 12 And the man said, The woman whom thou gavest to be with me, she gave me of the tree, and I did eat. 13 And the LORD God said unto the woman, What is this that thou hast done? And the woman said, The serpent beguiled me, and I did eat.”
Now, because of their sin, God sends Adam and Eve out of the Garden of Eden, and bans them from eating of the Tree of Life. Genesis 3:22-24 says, “22 And the LORD God said, Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever: 23 Therefore the LORD God sent him forth from the garden of Eden, to till the ground from whence he was taken. 24 So he drove out the man; and he placed at the east of the garden of Eden Cherubims, and a flaming sword which turned every way, to keep the way of the tree of life.”
It is only after this, after being sent out of the Garden of Eden, that Adam and Eve have any children. Genesis 4:1-2 says, “1 And Adam knew Eve his wife; and she conceived, and bare Cain, and said, I have gotten a man from the LORD. 2 And she again bare his brother Abel. And Abel was a keeper of sheep, but Cain was a tiller of the ground.” This means that there were no other people upon earth, while Adam and Eve were living in the Garden of Eden.
The New Testament confirms that Adam and Eve did not have any children until after they had sinned, and had been removed from the Garden of Eden. Romans 5:12 says, “Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned.” For the sin nature to have been passed upon “all men,” means that Adam and Eve had fallen into sin before they had any children.
We do not know how long Adam and Eve lived in the Garden of Eden before they sinned, or how old they were when they had Cain and Abel. No ages were listed here in Genesis 4:1-2, “1 And Adam knew Eve his wife; and she conceived, and bare Cain, and said, I have gotten a man from the LORD. 2 And she again bare his brother Abel. And Abel was a keeper of sheep, but Cain was a tiller of the ground.” The first age listed was when Seth, their third child, was born. Genesis 5:3 says, “And Adam lived an hundred and thirty years, and begat a son in his own likeness, after his image; and called his name Seth.”
So the answer to your question is that no one lived outside of the Garden of Eden, until everyone lived outside of it.