Yes, MCSO East covers everything east of I-17.
District 1 covers most of the Southeast Valley, east of I-17 and south of Northern Ave.
District 4 covers most of the Northeast Valley, east of I-17 and north of Northern Ave.
District 5 covers the Salt River recreation area and the recreational lakes. You may also hear deputies patrolling up and down AZ-87, the Beeline Highway, as well as Tonto National Forest law enforcement officers doing the same. MCSO East and MCSO Lakes 1 are frequently patched together, outside of summer weekends.
District 6 covers Queen Creek. I believe this jurisdiction extends slightly into Pinal County, by an agreement with PCSO. (I believe Queen Creek's incorporated boundries cross into Pinal County.) I think the agreement is bi-lateral, and PCSO deputies can sometimes be seen in and around Queen Creek. PCSO is fully encrypted on their new radio system, however, so you won't hear them.
District 7 is Fountain Hills.
District 8 is the Mountain district, covering the regional mountain parks. (Formerly known as District 6 Parks & Trails (D6 being shared with Queen Creek deputies at the time), and before that they were the Maricopa County Park Police until they were absorbed by MCSO.)
On MCSO West, District 2 covers everything west of I-17 and south of Northern Ave, and District 3 covers everything west of I-17 and north of Northern Ave.
John
Peoria