Always excellent local history blogger Dan Haneckow just put up a post about a small guide, circa the 1890s, of Portland's brothels.
The funny little handbook seems to have been mostly written, of course, in bawdy poems. It details various addresses of whorehouses around downtown and Old Town Portland. On what is now one block of the transit mall, for instance, there used to be a whopping four brothels.
Here's the section on Miss Minnie Reynolds of 89 Fifth Street:
In handsome parlors, skilled to please,
Fair Minnie waits in silken ease,
And at each guest's desire supplies
Dear pleasures, hid from prying eyes.
With such a haven ever nigh
Who could pass her parlors by?
And the then-and-now photo. This is Fifth Street and Miss Minnie's house is circled: