My mistake - make that half a mile *west* of Sheridan (not east). And it was on the south side of the creek, right by a very apparent beaver dam (which is perhaps a better landmark, being more unique to that spot).
We also definitely spotted a second male Blackpoll Warbler about half an hour later on the north side of the creek just off Dartmouth, about 200 yards west of the Mojo Wheels building.
Good birding,
-Max Miller, Denver