Flag created by CincyFlags for the neighborhood. 
Its symbolism, according to CincyFlags in [1]:
"Inspired by existing illustrations, this emblem represents the distinct Parkway Avenue circle just west of I-75.
Two bold lines of I-75 and Cross County Highway identify Hartwell as a Gateway Community; Hartwell is Cincinnati’s northernmost neighborhood. 
Maroon for the diverse community.
Emerald for the tree-lined streets in the Mill Creek Valley.

Ivory for transportation and the Hamilton &amp; Dayton Railroad station."
Own work using: https://www.cincyflags.com/hartwell
CincyFlags