"Federal" is to "Federally" as "State" is to
You've seen a bunch of suggestions, but when a single word is used in this context, it's overwhelmingly state.
Notice we pretty much always use "federally" with a passive verb. Since "federal" is an adjective, we need to turn it into an adverb so that we can modify a verb. But the noun "state" has no such problem.
- Federally-insured: state-insured
- Federally-owned: state-owned
- Federally-funded: state-funded
- Federally-subsidized: state-subsidized
- Federally-recognized: state-recognized (but only in a hurry)
You didn't explicitly ask for an adverb, so this definitely answers the question as you asked it. But you can also think of it this way: Not all adverbs end in -ly.
There are a few adverbs for governmental levels, but stately is not one of them.
For example, one quote in definition 2 for the entry "federally, adv." in the Oxford English Dictionary features municipally:
1940 Amer. Guardian 5 Apr. 4/3 The privateers never..reduce their rate unless forced to do so by public competition in the shape of municipally or federally owned [electric power] plants.
Municipally suggests a form of local control, like by a town or county government. In many countries, the next step up would be provincially or regionally, as this example from "provincially, adv." suggests:
1992 J. M. Bumsted Peoples of Canada vi. 190 During the Depression, Canadians thought regionally or provincially rather than nationally.
I've been able to uncover no adverb for state that is the equivalent of provincially or municipally. Instead, I've only found articles that refer to the US levels of government - state, federal, and municipal - as adjectives, while slipping in "federally, provincially, and municipally" when referring to Canadian tax collection ("Policing in Canada v. Policing in the US").
So you would be stuck saying something was state taxable (example), taxable by state (example), or taxable at the state level.
In American English and in the U.S., generally federally is to federal as state is to state level since there is no adverb for this meaning of the word state.
For example:
to be decided federally:
to be decided federally
VERSUS'
to be decided at state level
state-wise is slightly different. It just means: as regards or with regard to (the) states and it can't be used exactly like at (the) state level.
- Freedom of speech is federally protected by and in the U.S. Constitution.
- Freedom of speech is protected at state level in many states.
to be decided at state level
-wise in English means in reference to the preceding noun:
state-wise, goverment-wise, construction-wise
with regard to a or the state, government or construction (building)
It is not the adverb that matches federally.
The word Statal fits the question if you need an adjective. But I can't find reference to the adverbial 'statally', as in 'taxable statally'.
Definition of statal:
1 often capitalized : of or relating to a state (as of the U.S. or India)
: statal citizenship
: the statal economy
https://www.merriam-webster.com/dictionary/statal