100 is Southeast Valley (1840 S. Lewis, Mesa)
110 is Guadalupe Substation
200 is Southwest Valley (920 E. Van Buren, Avondale)
220 is Gila Bend Substation
300 is Northwest Valley (13063 W. Bell Rd, Dysart and Bell Rds, Surprise)
310 is Wickenburg Substation
380 is Sun City Posse HQ
390 is Sun City West Posse HQ
400 is Northeast (337622 N Cave Creek Rd, Cave Creek)
410 is Anthem Substation (3701 W. Anthem Way)
500 is Lake Patrol, (Usery Pass and Bush Hwy)
510 is Blue Point Substation
520 is Apache Lake Aid Station
540 is Canyon Lake Aid Station
550 is Saguaro Lake Aid Station
560 is Bartlett Lake Aid Station
570 is Lake Pleasant Ops Center
600 is Queen Creek (22626 S. Ellsworth Rd)
700 is Fountain Hills (Palisades Blvd and La Montana)
721 is Fountain Hills Posse HQ
730 is Rio Verde Substation (25615 N. Danny Lane)
800 is Mountain District (I don't know if they have a specific substation anywhere. They used to use the low 600 numbers when they were known as the Parks and Trails District. Before that, they were the Maricopa County Park Police, before being absorbed into MCSO.)