I believe that usually Locust Posts are not treated. They are a great choice.

Yes you are correct, not treated. Any thoughts on handling the holes? Gravel? Cement? Etc?

Some 25 years ago I erected a three rail split rail fence with wire screening - my back yard, About three hundred feet, three gates, all by hand and I was the only worker.

I dug each post hole with Fence Post Hole Shovel. I painted red rings around each handle so I knew how deep to dig and I did not have to use a tape measure for depth. The depth was that which I needed for the post plus about 4 more inches. This was to accommodate a flat stone that I lay in the bottom of the hole to set the post on.

I mixed concrete and shoveled it in for maybe ten - twelve inches and filled the rest with soil and any rocks that I had. Plumbed the post and supported with lumber.

Went on to the next hole and repeated. Would do this for a half dozen or so posts, and then drink beer and wait for the concrete to set up over night.

Next day, erect the rails between posts and then dig as before for more posts.

It worked fine and the neighbors agreed I had earned all the beer I drank.

25 years later I'm seeing more and more of the posts rotting out, typically at ground level.

If this helps, I've got some more tips for you. However, I'm sure there are some folks here with much more experience than I have!

That’s all good to know. I’d been plenty happy with 25 years I guess I should use concrete wasn’t sure if it was necessary or not

Get some more opinions - not all agree. I have no regrets, but....