Complex sentence: In 1805, several Irish natives were living on Fifth Street by the Ohio River, but due to exogamous marriages and removals to new residences this was the last concentration of the Scots-Irish/Ulster Scots in Louisville.
Split into simpler sentences: In 1805, several Irish natives were living on Fifth Street by the Ohio River, but due to various marriages and new residences. This was the last concentration of the Scots-Irish/Ulster Scots in Louisville.