The Revised Code of Washington (territorial-state) includes a fascinating section that explains the proper procedure for removing land from the registration roles of the de facto county’s government.
The legal implications of this removal are not known to me. But they seem to implicate the difference between the venues of “The State” (of the Union) and “this state” (territorial). It appears that the modern land “registration roles” for “Cook county” are “in this state” (territorial) while “registration” (If there is such thing) within “The County of Cook” presumes your land to be situated within The State (of the Union).
More, if you can remove your property from the registration roles of a county “in this state” and remove it back to The County of The State of the Union, the de facto gov-co of “this state” may not be able to continue to impose a property tax on it.