503
Area code
OR
United States geographic area code, in service since 1947-01-01. Part of the 503/971 overlay complex — ten-digit dialing required.
Statusin service
Introduced1947-01-01
JurisdictionOR, US
Local dialing10D
Time zonePacific
Last verified2026-09-17
Utilization 101% of assignable prefixes assigned
As of 09/17/2026
0%800 of ~792 assignable NXX values (200–999 excl. N11)100%
Prefix-level assignment does not equal number-level exhaustion; thousands-block pooling extends capacity. First assignment on record 2001-05-08, most recent 2026-09-03.
Area codes serve rate-center geographies, not municipal boundaries. “OR” identifies the jurisdiction, not an exact city footprint.
Top assignees
Ranked by assigned prefixes · initial assignee ≠ current carrier| Rank | Assignee | Prefixes | Share |
|---|---|---|---|
| 01 | QWEST CORPORATION | 222 | 27.8% |
| 02 | ZIPLY FIBER NORTHWEST, LLC DBA ZIPLY FIBER | 109 | 13.6% |
| 03 | NEW CINGULAR WIRELESS PCS, LLC | 71 | 8.9% |
| 04 | T-MOBILE USA, INC. | 56 | 7% |
| 05 | CELLCO PARTNERSHIP DBA VERIZON WIRELESS - OR | 54 | 6.8% |
| 06 | ELECTRIC LIGHTWAVE LLC DBA ALLSTREAM | 51 | 6.4% |
| 07 | TELEPORT COMMUNICATIONS AMERICA, LLC - OR | 34 | 4.3% |
| 08 | LEVEL 3 COMMUNICATIONS, LLC - OR | 30 | 3.8% |
| 09 | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 29 | 3.6% |
| 10 | SPOK, INC. | 22 | 2.8% |
Important: these are initial assignees from NANPA CO-code records — the carrier a prefix was originally assigned to. Because of number portability, the current serving carrier of any individual number may differ.
Change history
Recorded events for this NPA- 2006-12-21 Expansion of Concentrated NPA 971 Overlay with NPA 503 (Oregon)
- 1947-01-01Area code 503 entered service.
Planning letters & orders
Primary documents| Date | Document | Subject |
|---|---|---|
| 2006-12-21 | PL-359 ↗ | Expansion of Concentrated NPA 971 Overlay with NPA 503 (Oregon) |
| 1999-12-10 | PL-203 ↗ | Permissive Dialing Extended for the 503 / 971 Concentrated Overlay (Oregon) |
| 1999-07-21 | PL-182 ↗ | Concentrated Overlay of 503 (Oregon) NPA with 971 NPA |