I play on a public Realm and I wanted to make my base super far from spawn. But my dilemma - I went tote nearest stronghold and there was no stronghold. I loaded up a new world with that same seed at the same coordinates, and there was still no portal. I started checking multiple different strongholds in the area using the locate command, and none of them had a portal.
The stronghold was around 107,000 blocks away from spawn.