"Old Style" Alaskan State administered Mining Claims - river is "centerline" and the claim is 660 feet on either side away from the river for 1320 feet along the river centerline. Roughly 1320 x 1320 overall but oriented to the centerline of the river. 40 acres.
New system - find the corner of the pre-determined N-S, E-W square claim with sides and top running N-S and E-W and 1320 feet on a side. Use a GPS to locate pre-determined corner locations. 40 acre claim. You can incorporate 4 X 40 acre claims into a 160 acre claim with a single filing requirement but 4xs rental fee. As many individual 40 or 160 acre claims as you can afford with filing (Recorder's Office) fees and BLM claim rental fees ($35 - $140 per year for 40 Acre and 4 xs for 160 claim. Variable rate of $35 for first 5 years, 2xs that for another 5 years and then double THAT after 10 years. Recording fees ~ $20+ per sheet being recorded.
Federal administered claims use Alaska State administered claim system with the old way
very discouraged. Some states use that system of location and some don't - it's up to that state. No mining claims East of (about) The Mississippi River. $ fees for other states depend on the "official greed" of that state.
Just remember:
Us Alaskans have no fears
We give no damn for riches.
We spike our wine with turpentine
Us hardy sons of (female puppies).
Us Alaskans have no fears
We give no damn for trifles.
We hang our (spheres) upon the walls
And shoot at 'em with rifles.
Joe