Most counties have zoning ordinances, but often height limits will be expressed in terms of a multiple of the area of your property. For instance, if you own 10,000 square feet, you may build a building of 5000 square feet total, which would be a Floor-Area Ratio of 0.5. Chances are the zoning ordinance also has absolute height restrictions for most zones, but perhaps not Agricultural. However, many counties in the West do not have zoning, and a couple of states (I think) still don’t allow counties to exercise zoning powers. There are also the aforementioned Indian reservations.
Leaving that aside, your main problem in the US will be the presumption that any structure over 2000 feet above surrounding ground level is a hazard to avigation.
The ancient common-law rule was that a property owner owned from the center of the earth to the heavens: Cujus est solum ejus est usque ad coelum. However, at the end of World War II, the Supreme Court decided U.S. v. Causby, 328 U.S. 256 (1946), giving the federal government control over airspace needed for avigation. That came to mean all airspace above 2000 feet, and even lower altitudes near airports.
In 1965, seeing an increasing number of applications for radio masts more than 2000 feet high, the FAA promulgated this federal regulation:
14 CFR 77.13
(c) A proposed structure or an alteration to an existing structure that exceeds 2,000 feet in height above the ground will be presumed to be a hazard to air navigation and to result in an inefficient utilization of airspace and the applicant has the burden of overcoming that presumption. Each notice submitted under the pertinent provisions of this part 77 proposing a structure in excess of 2,000 feet above ground, or an alteration that will make an existing structure exceed that height, must contain a detailed showing, directed to meeting this burden. Only in exceptional cases, where the FAA concludes that a clear and compelling showing has been made that it would not result in an inefficient utilization of the airspace and would not result in a hazard to air navigation, will a determination of no hazard be issued.
As far as I can determine only one mast higher than 2000 feet has been approved since this rule was adopted, presumably on a showing of engineering necessity due to the foothills of the Sierra Nevada.