It just seems like such a small body of water and its Asian coast is accessible to people.
This question appears here quite frequently, so you might be interested in this response about the expansion of the Russia into Asia by u/Kochevnik81 as well as, this one by u/wotan_weevil and this one by u/The_Alaskan, both more directly related to the discovery of Alaska and this one by u/poob1x, focusing on early contacts between the inhabitants of western North America and Eastern Asia.