tower height

Does anyone know what the current limitations are for a tower approximately 3.5 Nautical Miles from an airport? The proposed location may be in the "instrument approach area," so i do not know whether the 200 FT or above policy to notify the FAA is subject to change to a different figure due to...

Any one know where to find information for the limitations on tower heights near an airport? location is approximately 3.5 nautical miles from the airport, but it's in the instrument approach area and i am unable to find if there are limitations for towers constructed in the concerned area.