Salem

Some guy's abandoned claim is in the way of my boundary stone. It says I need 1.2k authority to remove it.

The wiki says you need 2 silver per tile but its asking for authority? How does one gain more authority?

Please respond quick this is delaying my wall.

It is mostly the "same"... your authority of town influenced, how many money you be able to put in the Bell.
If it costs 1200 Silver to remove a claim, you need a townbell with at least this amount of Authority.

Get the stone covered by the village claim by using border stones and build banners until you have the authority to ED the claim stone. The banners (cross of saint george) increase your max authority but also increase the tax for keeping the bell. Once the authority is up where you need it (1200, as kralith says), load it with silver and erase the claim then smash the banners and unneeded border stones. Using eminent domain (ED) will consume the authority in your bell, so be ready to load more silver into it after you've accomplished what you set out to do. Just remember that banners can't be built inside the influence of other banners.

My authority cap is like 4.5k already XD

I dunno it might be more efficient to just make a crime alt to destroy the claim since there is already an opening in the wall.