99% of Cheras Selangor is under MPKj since it lies under two mukims administered by MPKj - Mukim Cheras and Mukim Hulu Langat (Bdr Mahkota Cheras, SL2 and Venice Hills are under the latter mukim). Meanwhile, 1% of Cheras Selangor is under MPAJ since it lies under Mukim Ampang. The areas of Cheras under MPAJ are Taman Bukit Segar Jaya, Taman Cheras Hartamas, Kg Cheras Baru and Taman Cheras Indah.
Cheras Hartamas (CH) is kinda unique as the northern part is under MPAJ, while the southern part is under MPKj. Both parts of CH uses the same postcode of Cheras Selangor that is 43200, although the Ampang side of CH also use 68000 Ampang and 56100 Kuala Lumpur (postcode of Pandan Indah). 56100 is mainly used by Kg Cheras Baru and Taman Cheras Indah.. (I've heard of Cherasians that use the 43200 postcode for the latter, as I have a friend that lives in Taman Cheras Indah and uses 43200 in their postage address.)

Half Cheras, half Kajang..