Halal street  is located near  the Chiang mai night market , this is the one the best place for to eat  Halal Thai food in Chiang mai.
At the enterance of the soi /street there is a  famous Chinese mosque, This mosque was build by Chinese Muslims settled in Thailand, they migrated to Thailand  from Yunnan china.
There are 5 to 6 Halal thai restaurants, serving the famous northern dish Halal ” khao Soi” as well as some other traditional  northern Thai dishes ,
the restaurants are neat and clean ,while the name of the restaurants and the sign boards are still maintained in traditional style mix of chinese and thai language.
from this place you can pick up northern style halal Thai snacks which are usually difficult to find in Bangkok
best time to visit this place is between 10.00 am to 6.00 pm

here is the location on google map