The following is from the must have book, "Know the Sasquatch/Bigfoot: Sequel & Update to Meet the Sasquatch" by Christopher L. Murphy. You can buy it here.
If sasquatch do exist in North America, they have been here a very long time and would predate all of the foregoing stone carvings. We can reason that the creatures came here from Eurasia by crossing the land bridge that connected Eurasia to what is now Alaska (across the present Bering Strait). This passage was usable for at least 20,000 years, and indeed was used both ways by human hunters on the trail of arctic game. However, by about 8000 BC, anyone or anything that was in North America was here to stay if they did not possess a boat. By this time, melting ice sheets had drastically raised the sea level so the Bearing Strait area could no longer be crossed on foot.
Given the 8000 BC "no return" time frame, we can say that sasquatch have been here for at least 10,000 years. As to the maximum time, it is probably around 30,000 years, given that the land bridge existed for about 20,000 years.
ONE WILD CREATURE IN OUR FORESTS DEFINITELY CAME FROM ASIA
JOHN GREEN TOLD US: "I was present when droppings of any unusual appearance were collected in Northern California and shipped off for examination. The report that came back was that the material was the remains of fresh water plants, and that it contained eggs of parasites otherwise known only from some North American tribal groups in the northwestern U.S., pigs from south China, and pigs and people from southwest China." Because the material did not appear to have originated with either people or pigs, and the Asian parasites that laid the eggs did not get here by themselves, we might consider the sasquatch as a highly likely suspect for the droppings.
You can purchase the book, "Know the Sasquatch/Bigfoot: Sequel & Update to Meet the Sasquatch" by Christopher L. Murphy here.