| City: | Simpsonville, Maryland |
| County: | Howard County |
| Timezone: | Eastern (GMT -05:00) |
| Local Time: | 2:21:16 AM |
| Population: | No Population Data |
| Area Codes: | 227 / 240 / 301 / 410 / 443 / 667 |
| Classification: | PO Box |
| Coordinates: | 39.1857, -76.8776 |
| Quick Link: |
Simpsonville no longer exists as a separate town. ZIP code 21150 preserves the name of a historic Maryland community now absorbed into Columbia, the planned city developed by James Rouse in Howard County. The post office sits within the Kings Contrivance village, one of Columbia's ten residential villages.
This is a PO Box Only Zone, meaning there's no street delivery alternative. All 117 PO Boxes serve customers who can't receive mail at their physical addresses through this ZIP. The enclosing ZIP 21046 (Columbia) handles street delivery for the surrounding area. With 119 business delivery points but zero residential population counted by the Census, 21150 functions primarily as a commercial mailing address.
The only street in the ZIP+4 database is Shaker Dr, which has 24 address records with UNIT designators. This pattern suggests a single commercial complex or business park rather than residential development. General Delivery service is available for those without a permanent address.
Simpsonville's ZIP code persists as a postal artifact. The community's identity lives on through its post office, even as the surrounding landscape transformed into suburban Columbia. Residents of Kings Contrivance, Hickory Ridge, and McGills Common neighborhoods can rent PO Boxes here while receiving street mail through neighboring ZIP codes.
Single street with UNIT secondary addresses suggests commercial or business park setting.
ZIP Code 21150 is designated for PO Box delivery only; business establishment and employment data are not available.
| # Residential Mailboxes: | 0Source: USPS |
| # Business Mailboxes: | 0Source: USPS |
| Total Delivery Receptacles: | 603Source: USPS |
| Single Family Delivery Units: | 0Source: USPS |
| Multi Family Delivery Units: | 0Source: USPS |
| # of Businesses: | 0Source: CBP |
| 1st Quarter Payroll: | $0Source: CBP |
| Annual Payroll: | $0Source: CBP |
| # of Employees: | 0Source: CBP |
ZIP Code 21150 is located in Howard County, Maryland, within the Baltimore-Columbia-Towson, MD Metropolitan Statistical Area (CBSA 12580) and Maryland's 3rd Congressional District. This Metro area has a population of 2,839,409 people, about 0.00% of whom live in ZIP Code 21150. It covers 0 sq mi of land and a water area of 0 sq mi.
| CBSA Name: | Baltimore-Columbia-Towson, MDSource: Census |
| CBSA Number: | 12580Source: Census |
| CBSA Type: | MetroSource: Census |
| CBSA Division: | --Source: Census |
| CBSA Population: | 2,839,409Source: Census |
| MSA: | Washington-Baltimore, DC-MD-VA-WV CMSASource: Census |
| Land Area: | --Source: Census |
| Water Area: | --Source: Census |
| Congressional District: | 03Source: USPS |
| Congressional Land Area: | 304.14 sq miSource: Census |
| PMSA: | Baltimore, MD PMSASource: Census |
| Intro Date: | < 2004-10Source: ZIP-Codes.com |
| Place FIPS Code: | --Source: Census |
| Place Name: | --Source: Census |
We could not locate which school district 21150 belongs to, but we will update this once new district data is released. There are no public schools nor private schools with a mailing address in this ZIP Code. Listing Nearby schools instead. It also has 6 colleges, universities or post secondary education institutions nearby which would be a short commute to.
Our sources include trusted federal and licensed data from the United States Postal Service, U.S. Census Bureau, U.S. Geological Survey, Centers for Medicare & Medicaid Services, and the National Center for Education Statistics, along with proprietary datasets created by ZIP-Codes.com. Data last updated on February 1, 2026.