"where's that to?"
Solution 1:
The OED, s.v. "to", meaning A.4.a, says
a. Expressing simple position: At, in (a place, also fig. a condition, etc.). Cf. German zu Berlin, zu hause. Now only dial. and U.S. colloq. Cf. home n.1 and adj. Phrases 1e.
It gives examples from 925 to 1977, including this from 1899:
In Somerset‥it is correct to say ‘I bought this to Taunton’.