Last official estimate I recall was 12 million, and you're right, this is nuts.
Illegal or not, they can register to vote (Democrat, of course) by just applying for a driver's license (we'll pay for a translator, if one is needed). And state DMVs are told not to ask about citizenship.
Then, with a driver's license, they can apply for a Social Security card and credit cards which they can use to buy tickets and on and on and on.
We are snake-bit and if somebody doesn't apply a tourniquet soon, the venom we have let into this country will do us in.
Why don't local lawmen call in the Feds in a case like this?