To completely remove the unmerged commits and start fresh (as if the branch was just created), you can reset it to the commit where it diverged from the main branch or to any specific commit you want to go back to. Use the git log command to find the commit ID you want to reset to.

Think of a Git branch as a movable bookmark in your project's history. The unwanted commits are pages after the point where you want the bookmark to be. Resetting the branch moves that bookmark backward; it does not require deleting the branch itself.

Before changing anything, create a backup pointer:

git switch your-branch
git branch backup/your-branch-before-reset

The second command creates another branch pointing to the current commit. If you reset to the wrong place, your original work is still reachable through the backup branch.

Next, inspect the history:

git log --oneline --graph --decorate

Find the last commit you want to keep, then move the current branch to it:

git reset --hard <commit-to-keep>

reset moves the branch pointer. --hard also makes the working directory and staging area match that commit, so uncommitted changes will be discarded. If you need to preserve local changes, stop and use --soft or --mixed instead.

If the unwanted commits were already pushed, the local and remote branches will now disagree. Update the remote with:

git push --force-with-lease origin your-branch

--force-with-lease is safer than --force: it refuses to overwrite the remote branch if someone else updated it since your last fetch.

If this is a shared branch, coordinate with the other contributors first because rewriting its history changes the commit IDs they have locally.

After confirming that everything is correct, the backup branch can be removed:

git branch -d backup/your-branch-before-reset