All I can think of are the very important agreements/partnerships between the US and Canada to protect the Great Lakes - the International Joint Commission, Great Lakes Charter, Great Lakes Water Quality Agreement and the Great Lakes-St Lawrence Deep Waterway Treaty. I'm sure it's fine though. /s
UPDATE: It appears the order does indeed disallow our government from recognizing the existence of a Lake Ontario in any contract. That's exactly what I was talking about. Trump has now made it impossible for the United States to engage in diplomacy over this major body of water.