Use standard US English spelling for all words unless the word is a non-US English spelling within in a quote. If in doubt on how to spell a word, use the online Merriam-Webster dictionary.
If a word is misspelled in a quote, only use [sic] after the error if correcting the error alters the impact of the quote. It is fine to correct typos within a quote, and there is no need to draw attention to such errors.
For geographic and place names, use the USGS Geographic Names Information System (GNIS) as the source for spelling.