I'm a lurker in this group.

But I was curious if anybody has the exact coordinates for the
geographic extremes for Russia since it straddles the 180 Meridien.

The United States has "through the looking glass" extremes because
the Aleutians in Alaska straddle the Meridien (in which Alaska has
the North, East and West geographic extremes for the U.S.)

West Point on Amatignak Island at 179° 06' 31" west is considered
the extreme west point of the U.S.

Pochnoi Point on Semisopochnoi Island has coordinates of 179° 46'
East is only 70 miles WEST of Amatignak but it gets the East
designation.

And just to make things interesting the Aleutians continue another
300 miles WEST to Cape Wrangell on Attu Island at 172° 54' East
Even though Attu Island is as far as you can go from right to left
on a map for both Alaska and the U.S. it doesn't count as any
extreme by our traditional ways of determining this.

Presumably Russia would have similar looking glass coordinates
although perhaps not quite so dramatic since the 180 meridien
crosses a big swath of Siberia (so the east/west Russia extremes
would be either side of it for its length). In most maps you
usually don't see this as they show the manually adjusted zig
zagging dateline.

I was just curious to find the official coordinates on how far
Russia extends into the Western Hemisphere.