Question: What County that was incorporated on June 25, 1789 and named for John Hancock, has a short stream  from its source the river runs 5.4 mi south to its confluence with Mill Brook in Eastbrook?
Sentence (from "Maalbeek"): It is a tributary of the Zenne, which it joins up in Schaerbeek, from its source located to the south near the Abbey of La Cambre.
Relevant evidence: No