One must look at it through "their" eyes. For example, even prior to that great upheaval, the Northwest TErritory aka the NOrthwest was Illinois, Wisc, Mich, etc. A big chunk of your west "were" was not even states yet. Again as Bryan said, the North and South was more a geo-political/socio-demographic state of mind and not geographical. Arkansas is a prime example of a southern/frontier state. Areas tied very closely to the South and others tied more to the independent frontier of the other areas of the Trans Miss. And again, it all depended on where those people who lived there associated in their minds what region they were loyal to. The far western territories were considered slave territories (New Mexico, Arizona) and geo-politically were more tied to the South than the North. This was specifically a political move. Those areas would support such a limited and small amount of slave owners and slaves that in my mind it was ludicrous to think they could carry on the plantation system except along the better rivers. However, the whole slave issue was not about human rights etc but who would control the gov't...an agricultural South (economy based on slavery) or an industrial North. At that stage of things, a gov't that supported one could not support the other. Policies that protected business, industry and cities would hurt those for agriculture and visa versa. Therefore, the one major aspect of this that it seems the famous authors never seem to grasp, in my opinion is exactly what was the argument over slavery... not to free or give them equality but that plain and simple, the South's economy was agriculture based on slavery and the north was based on industry using immigrant labor. The whole argument was about controlling the govt. The more I think about it things haven't changed much now. COnservative vs Liberal. If the South had won, I bet the South and "West" would not be having many of the issues we currently seem to have. THe only hitch would have been with the slaves who would probably have been phased out as technology advanced. That is the one negative though that hampered the entire stance of the South. Wow, I really got off on a tangent here and away from the original intent. North and South of the 1860's was not totally geographical and those "western" states did participate on one side or the other based upon the geographical origins of their inhabitants.