Washington area codes — detailed data

NANPA NPA database, current as of July 28, 2026.

This page expands the state overview with per-code operational data from NANPA: parent codes, projected exhaust dates, dialing patterns and relief status for all 6 Washington codes.

Aggregate footprint: the state's 6 geographic codes currently carry 3,523 active NXX prefixes over 255 rate-center anchorings, with 2,332 prefixes in thousands-block pooling. 6 of the codes serve territory inside FCC top-100 metropolitan statistical areas.

Lineage: 253 came out of 206 in 1997; 360 came out of 206 in 1995; 425 came out of 206 in 1997; 564 came out of 360 in 2017. The remaining codes (206, 509) date back to the plan's early assignments.

Dialing plans: 6 codes use plain ten-digit local dialing (10D). Overlay territories always dial ten digits; the 2021 988-hotline transition moved most others to ten digits as well.

The tightest capacity in the state is 509, projected to exhaust 3Q 2029.

Status: no Washington code is currently in jeopardy or active relief planning — capacity is adequate near-term per NANPA.

Code-by-code notes

360 — spawned 564; carved from 206; overlaid by 564; exhaust forecast 4Q 2057.

509 — exhaust forecast 3Q 2029.

206 — spawned 360, 253, 425; overlaid by 564; exhaust forecast 2Q 2073.

425 — carved from 206; exhaust forecast 1Q 2044.

253 — carved from 206; exhaust forecast 2Q 2056.

564 — carved from 360; overlaid by 206; exhaust forecast 4Q 2057.