where was myeong o body being hidden

Myeong-o’s body was hidden in the sea near the ferry/boat area after he was killed, and it was later pulled back into the story as part of the evidence trail.

What the show implies

The key point is that the body was not buried somewhere on land; it was concealed in water to delay discovery and complicate the investigation.

Why it matters

That reveal also tied Yeon-jin more closely to the case because trace evidence connected back to her.

In plain terms

So, the answer is: it was hidden in the sea, not in a building or grave.