at , in : Always in a country; either at or in a city, town, or village; at, if the place is regarded as a point; in, if it is inclusive; as, “We arrived at Paris;” “He lives in London.”

at : Commonly but erroneously used for to, as an intensive in such phrases as “Where have you been at ?” “Where are you going at ?” Used also occasionally to denote place: as, “Where does he live at ?” Wherever used in such connections the word is redundant.

At, At and To, At All.—The presence of at  improves such constructions as “He is at  home,” instead of “He is home.” At  and to  are superfluous in such sentences as, “Where is he?” and “Where has he gone?” hence, their use should be avoided. At all is superfluous in such sentences as, “There is no use in your going;” “I do not know him.”
prep. at, in, with, from, of, amongstVariants: et, æt, ed, at, used with the infin. mood, Comb.:atte,, at the,ate, ette, eter, atten, at-after, after att-alle, in every way at-foren, before,; et-foren, at-uore, at-om, at home, at-on, at one, in accord at oon, at-ones, at once, together, attonis, attonys, attones
pron. rel. and conj. that —see Þat