Kiambu postal codes are managed by the Postal Corporation of Kenya (Posta), which is responsible for sorting and delivering mail in the county, in addition to enhancing logistics. Kiambu is Kenya’s Most Populous County, with more than 2.4 million residents and the second-largest economy with a GDP of $16.78 billion. The main postal code for Kiambu County is 00900; however, the county has many other postal offices located in its sub-counties, each with a different postal code number.
Kiambu County borders Nairobi and Kajiado Counties to the South, Machakos to the East, Murang’a to the North and North East, Nyandarua to the North West, and Nakuru to the West.
Kiambu County at a Glance
Attribute | Value |
---|---|
County Headquarters | Kiambu Town (Executive in Thika) |
Primary Postal Code | 00900 |
Total Sub-Counties | 12 |
Total Constituencies | 12 |
Total Area | 2,538.7 km² |
Population (2019 Census) | 2,417,735 |
GDP (PPP, 2022) | $16.78 billion |
Postal Service Coverage | 100% (all sub-counties) |
Dominant Tribe | Kikuyu |
Key Economic Sectors | Manufacturing, Dairy, Real Estate |
Below is a Map For Kiambu County:

What is the postal code for Kiambu?
Kiambus’s Postal Code is 00900, referring to its main general postal office located in Thika Town. However, like all counties, Kiambu’s postal codes are managed by the Postal Corporation of Kenya, and thus, its postal code is closely tied to how the County itself is structured and administered.
Kiambu’s governance follows Kenya’s two-tier system: national and county administrations. The national framework divides Kiambu into sub-counties (headed by Deputy County Commissioners), locations (Chiefs), and sub-locations (Assistant Chiefs). Parallelly, the county government uses constituencies (governed by MPs) and wards (MCAs) for service delivery.
Kiambu County has twelve constituencies, which are further divided into 60 electoral wards, each with its own postal code.
Additionally, the Postal code for Kiambu County is made up of five-digit numbers, with each digit carrying a very special Purpose:
- Last Three Digits (Suffix): The remaining three digits pinpoint the specific delivery office or area within Nairobi. These numbers are assigned based on administrative divisions, significant landmarks, or institutional zones.
- First Two Digits (Prefix): The first two digits identify the broader geographical region or County. For Nairobi, this prefix is consistently “00,” immediately signaling to postal workers that the destination is within Kenya’s capital city.
Kiambu Postal Codes
# | Name | Type | Headquarters / Location | Postal Code |
---|---|---|---|---|
1 | Gatundu North | Sub-County | Gatundu | 01030 |
2 | Gatundu South | Sub-County | Gatundu | 01030 |
3 | Githunguri | Sub-County | Githunguri | 00216 |
4 | Juja | Sub-County | Juja | 01028 |
5 | Kabete | Sub-County | Kabete | 00604 |
6 | Kiambaa | Sub-County | Kiambaa | 00219 |
7 | Kiambu | Sub-County | Kiambu Town | 00900 |
8 | Kikuyu | Sub-County | Kikuyu Town | 00902 |
9 | Lari | Sub-County | Lari | 00220 |
10 | Limuru | Sub-County | Limuru | 00217 |
11 | Ruiru | Sub-County | Ruiru | 00232 |
12 | Thika Town | Sub-County | Thika | 01000 |
13 | Gathiruini | Town | – | 00239 |
14 | Githiga | Town | – | 00903 |
15 | Ikinu | Town | – | 00904 |
16 | Kamiti Prison | Prison Facility | – | 00607 |
17 | Tatu City | Industrial Zone | – | 00232 |
18 | JKUAT (Jomo Kenyatta Univ.) | University | Juja | 00625 |
19 | Kenyatta University | University | – | 00609 |
20 | Mount Kenya University | University | Thika | 01000 |
21 | Kijabe Boys High School | Secondary School | Kijabe | – |
22 | Kiambu County Hospital | Hospital (Level 4) | Kiambu Town | 00900 |
23 | Thika Level 5 Hospital | Referral Hospital | Thika | 01000 |
24 | Ruiru Sub-County Hospital | Hospital (Level 4) | Ruiru | – |
25 | County Government HQ | Govt Office | Kiambu Town | 00900 |
26 | Governor’s Office (Thika) | Govt Office | Thika | 01000 |
27 | Ruiru Sub-County Administrator | Govt Office | Ruiru | 00232 |
Frequently Asked Questions (FAQ)
What is the main postal code for Kiambu Town?
Kiambu Town’s primary postal code is 00900.
How many sub-counties are in Kiambu County?
Kiambu has 12 sub-counties: Gatundu North, Gatundu South, Githunguri, Juja, Kabete, Kiambaa, Kiambu, Kikuyu, Lari, Limuru, Ruiru, and Thika Town.
Which university in Kiambu uses postal code 00609?
Kenyatta University (Main Campus) in Ruiru.
Is Ruiru’s postal code shared with Tatu City?
Yes, both use 00232, as Tatu City lies within Ruiru Sub-County.
What is the postal code for Limuru’s headquarters?
Limuru’s central postal code is 00217.