US lakes & pondsUS lakes & pondsSurface area: The USGS National Hydrography Dataset outline (NHD Permanent ID 130909442).
The red circle marks Lake Number Twelve.
Towns and counties: U.S. Census Bureau boundaries overlaid on the USGS lake outline (Washington: incorporated places touching the lake, otherwise the nearest one).
Official WDFW pages. Rules and fees change; check before you go.
Built only from the data on this page: official access lists, OpenStreetMap beaches and trails, campground listings, state and USGS invasive-species records. We don't rate crowds or water quality.
Numbers on the map match the list at rightbelow.
Shoreline: USGS National Hydrography Dataset (NHD Waterbody, Permanent ID 130909442), public domain. State outline: U.S. Census Bureau TIGERweb. Points: WDFW water access sites. Interactive map: Leaflet with © OpenStreetMap contributors. Not for navigation.
We found 8 campgrounds and RV parks within 15 miles of Lake Number Twelve, 2 of them within 5 miles. Distances are straight-line from the nearest point on the shoreline, so driving distance is longer.
RVs welcome
Electric hookups · Showers · Toilets · Dump station
RVs welcome · Tent sites · Toilets
RVs welcome · Tent sites
Electric hookups · RVs welcome
Electric hookups · RVs welcome · Dump station · Wi-Fi
All campgrounds & RV parks in Washington
Green tent icons on the lake map mark campgrounds near the shore, and the interactive map shows the closest 12. Amenities are listed only where a source records them; call or check the campground's website before you go, since seasons and rates change every year.
Campground data: OpenStreetMap contributors (ODbL). Pulled Oct 12, 2026.
Live from the National Weather Service API for the lake's coordinates (47.3251, -121.9757). The nearest station may be several miles away. NWS forecast for Lake Number Twelve. No live water-temperature sensor is shown because we haven't found a public one for this lake.
Based on solunar theory, an estimate. Major periods (about 2 hours) center on when the moon is directly overhead or underfoot; minor periods (about 1 hour) center on moonrise and moonset. The 0–100 activity score rises during those periods and gets a boost near sunrise and sunset and around the new and full moon. Weather, water temperature and pressure often matter more. Sun and moon times are calculated in your browser from the lake's coordinates with standard astronomy formulas, shown in PT (America/Los_Angeles), and accurate to within a few minutes.
1 public access site listed.
| Site | Town | Owner | Type | Parking | Fee | Uses | Map |
|---|---|---|---|---|---|---|---|
| Lake Number 12 Water Access Site | Black Diamond | WDFW | Carry-in (hand launch) | — | — | Boating | 47.3240, -121.9721 |
Fees, hours and rules change; confirm with the site owner before you go.
Reported on or near Lake Number Twelve
USGS Nonindigenous Aquatic Species database
USGS records matched to this water by location (within about 150 m of the outline) or by the place name in the record. A record shows a sighting was reported; it doesn't prove the species is still there. As of Oct 10, 2026.
Lake Number Twelve covers about 41 acres in Black Diamond, Washington (King County).
No trailer ramp is listed, but there is 1 public access site for car-top boats or shore access.
Yes. We list 8 campgrounds and RV parks within 15 miles, 2 of them within 5 miles.
Lake Number Twelve touches Black Diamond in King County, Washington.
Know Lake Number Twelve? Tell us about the launch, parking, where they're biting or anything a first-time visitor should know. Tips go privately to the LakeRipple editor; nothing is posted automatically. Helpful tips may be featured on this page (we'll use your first name only if you give one).
Straight-line distance between lake centers. All Washington lakes & ponds · All waters in Black Diamond