In Store -> Tax, you could bulk import the tax regions along with the tax rates. Click "Import Tax Regions" button. Select a tax region file and click "Import" button.
Here is the description of the tax region file.
The tax region file is basically a text file. Each line define one tax region.
<Tax Region Name>,<Tax Rate>,<Conditions Seperated by semi colons>
Here is an example of tax region file:
NY Sale Tax,0.11,Country=US;State=NY
CA Orange County Sale Tax,0.15,Country=US;State=CA;City=Orange