Which preposition to use with lathrop

by Occurrences 1%

So I was headin' for Lathrop by a trail I'd run across that took around the mountain, and meanin' to keep on as long as I could durin' the night, when all at once something flew up and hit me ker-slap!

on Occurrences 1%

He was just returning from an errand on which Mrs. Hamilton had sent him, when he overtook Fred Lathrop on his way uptown.

Which preposition to use with  lathrop