What is the length of the US coastline from northern Washington State to the south end of California (in miles)?

According to Office of Coastal Management at the National Oceanic and Atmospheric Administration, the length of the coastline from Washington state to California is 7,863 miles [12,655 km]

3,026 miles Washington
1,410 miles Oregon
3,427 miles California

https://coast.noaa.gov/data/docs/states/shorelines.pdf
https://www.worldatlas.com/articles/us-states-by-length-of-coastline.html

I'm not sure how trustworthy these websites are. For instance, the shorelines one gives Louisiana's coastline as 7721 miles, while the other says 397. The first says Alaska has 33904, while the second says 33904 in one place and 6640 in another.

A fairly good explanation for the differences can be seen at https://en.wikipedia.org/wiki/Coastline_paradox The length of a coastline depends on how you measure it. It can be how far it takes to sail round it, how far to walk round it with one of those little wheelie things, or how far by running a tiny wheelie things round the outline on a map. Or if you are doing it by higher methods, it involves fractals. Does a bay like, for example, the narrow ended Mersey Estuary count as coastline, and if so, how far up do you count it? Or take the Bristol Channel and Severn Estuary. Where do you draw the line between sea and river? And what about islands you can walk to at low tide? Where you have cliffs, tidal rise and fall is a vertical consideration. Where I live, tidal rise and fall is more a matter of horizontal mileage, although the vertical element does come in when a vehicle is stuck in the sand over a mile out (the headlamps were a pinprick of light in the distance, and went out as we looked).

Let me try to help. NOAA distinguishes between coastlines and shorelines. The numbers quoted so far have been for shorelines. The coastline is the general outline of the specified coast and generally only includes genuine maritime frontage. Shorelines include all tidal waters down to a 100 foot (30 meter) width on estuaries. Washington state has a coastline of only 157 miles (253km), but a 3026 mile (4868 km) shoreline, due to the great size of the Puget Sound complex and its many islands.
The total COASTLINE for the three states is 1293 miles/2070km (CA 840/1350km, OR 296/476km, and WA 157/253km).