Newcastle is a city in King County, Washington, home to about 12,989 people across 4.5 square miles. It has no ZIP code of its own: it’s part of 98056 and 98059.
Homes sold for a median of $459 per square foot across 2 ZIP codes in the three months ending August 2026, and all of them were seller’s markets.
Mostly Renton; part is in Newcastle
Mostly Renton; part is in Newcastle
Each card is that ZIP code’s whole market, including any part outside Newcastle. Seller’s market: under 4 months of supply; buyer’s market: over 6. Methodology
We’re writing up Newcastle’s story and what everyday life there is like, for people thinking about moving in.
Are you a local agent who knows Newcastle well? Agents who advertise here will be able to write the guide. Advertise on OfferBacked
| Nearest major airport | Seattle–Tacoma International Airport (SEA)9 miles away |
|---|---|
| Nearest city of 250,000+ | Seattle, WA12 miles away |
Straight-line distances from the center of Newcastle; driving is longer.
Source: Airports from OurAirports (scheduled passenger service); city centers and populations from the U.S. Census Bureau.
Source: Members of Congress from the congress-legislators project; districts from the Census Bureau’s relationship files; governor and mayor from Wikidata.
Newcastle had 13,017 residents in the 2020 census, up 68% since 2000.
It’s the 104th largest of 628 towns in Washington by population.
King County grew from 110,053 residents in 1900 to 2,269,675 in 2020.
King County, 1900–2020
Source: U.S. Census Bureau decennial censuses (counties 1900–1990 from the Bureau’s historical county file).
Average highs peak around 78°F in summer, and winter lows average 37°F. About 34.6 inches of rain and melted snow fall in a typical year.
Source: NOAA 1991–2020 climate normals, Renton Muni Ap, WA weather station (3 miles away).
1,305,947 jobs at 70,376 businesses in King County. The biggest industries by employees:
Source: U.S. Census Bureau County Business Patterns 2023 (private employers; jobs counted where people work).
258 doctors and other health care providers list an office in Newcastle’s ZIP codes.
Nearest hospitals
Providers with an office here
| Primary care doctors | 48 |
|---|---|
| Specialist doctors | 6 |
| Dentists | 36 |
| Nurse practitioners and physician assistants | 23 |
| Mental health providers | 56 |
| Physical and occupational therapists | 64 |
| Optometrists | 14 |
| Chiropractors | 11 |
| Pharmacies | 11 |
Source: Hospitals from CMS Hospital General Information (ratings are CMS overall star ratings); straight-line distances; providers from the CMS National Plan and Provider Enumeration System (NPPES), by practice address and primary specialty.
Parks (18 nearby)
Grocery stores (4 nearby)
Pharmacies (1 nearby)
Libraries
Museums
Theaters and performance venues (1 nearby)
Counts are within about 1.5 miles of the center of town.
Source: Map data © OpenStreetMap contributors (openstreetmap.org/copyright), as mapped by volunteers; it can miss places or include closed ones.
Public schools here are run by Issaquah School District, Renton School District, Tukwila School District and others. Check each district’s attendance zones for a specific address.
| School | Grades | Students | Type | Distance |
|---|---|---|---|---|
| Apollo ElementaryRenton | Pre-K–5 | 496 | Public | 0.7 mi |
| Briarwood ElementaryRenton | Pre-K–5 | 630 | Public | 2.1 mi |
| Meadow Crest Early Childhood Education CenterRenton | Pre-K | 490 | Public | 1.7 mi |
| Newcastle Elementary SchoolNewcastle | Pre-K–5 | 451 | Public | 1.5 mi |
| Hazelwood Elementary SchoolNewcastle | K–5 | 478 | Public | 2.8 mi |
| Highlands Elementary SchoolRenton | K–5 | 386 | Public | 1.9 mi |
| Hilltop Heritage Elementary SchoolRenton | K–5 | 576 | Public | 0.7 mi |
| Kennydale Elementary SchoolRenton | K–5 | 511 | Public | 2.5 mi |
| Maple Hills ElementaryRenton | K–5 | 460 | Public | 4.8 mi |
| Maplewood Heights Elementary SchoolRenton | K–5 | 395 | Public | 1.7 mi |
| Sierra Heights Elementary SchoolRenton | K–5 | 323 | Public | 1.1 mi |
| Griffin HomeRenton | 6–12 | — | Special Education | 2.8 mi |
| Maywood Middle SchoolRenton | 6–8 | 826 | Public | 2.8 mi |
| McKnight Middle SchoolRenton | 6–8 | 811 | Public | 1.8 mi |
| Vera Risdon Middle SchoolNewcastle | 6–8 | 751 | Public | 3.0 mi |
| Hazen Senior High SchoolRenton | 9–12 | 1,796 | Public | 0.5 mi |
| Liberty Sr High SchoolRenton | 9–12 | 1,495 | Public | 2.3 mi |
| Renton Technical CollegeRenton | 9–12 | — | Alternative Education | 1.8 mi |
| Renton Technical High SchoolRenton | 11–12 | 66 | Public | 1.9 mi |
| YouthSource and RTCRenton | 11–12 | 296 | Alternative Education | 1.9 mi |
| School | Grades | Students | Affiliation | Distance |
|---|---|---|---|---|
| New Life MontessoriNewcastle | Pre-K–K | 3 | Christian (no specific denomination) | 2.3 mi |
Source: U.S. Department of Education, NCES: Common Core of Data (2024-2025) for public schools; Private School Universe Survey (2023-2024) for private schools. Listed by address; we don’t rate schools.
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Shares ZIP codes with Renton and East Renton Highlands.
Town boundaries don’t always match ZIP codes: a ZIP code can cross into neighboring towns, and a town can share a ZIP code with its neighbors. Facts describe the town itself; market figures describe whole ZIP codes.