I spotted this unimproved foot trail before I realized there was a city park on the other side of the creek. It is here I snagged a low leaning branch and tore the better part of my t-shirt off.
Saturday, May 15, 2021
45.48396388888889, -122.77825277777778
google map 
45.4842722, -122.7777815
45.48433055555556, -122.77757222222222
45.484405555555554, -122.77612222222223
BOUNDARY 45.4832897, -122.7791425
BOUNDARY 45.4852519, -122.7751660
At this point I doubled back to Chestnut Place and rode the proper trail around the park.
My maps don't name this creek or show a source or downstream. Having studied DataBasin contours it likely runs underground to Little Peoples Park due west.
pages/mcmillan-park