evidence: If the Republic of Ireland had the same population density as England, its population would be around 30.2 million people – lower than in the claim.. However, Ireland can also refer to the island of Ireland. If it had a similar population density to England, its population would be around 36.1 million people – which is indeed approximately 35 million. [...] So if the island of Ireland had a similar population density to England, its population would be ((69700+13547) x 433.5) = 36.1 million people.