Viscount St Lawrence is in Viscount Ireland.
On 3rd September 1767 Christopher aka Stephen St Lawrence 1st Baron Howth -1430 [aged 37] was created 1st Earl Howth, 1st Viscount St Lawrence.
On 29th September 1801 Christopher aka Stephen St Lawrence 1st Baron Howth -1430 [aged 71] died. His son William [aged 48] succeeded 2nd Earl Howth, 2nd Viscount St Lawrence, 16th Baron Howth.
On 4th April 1822 Christopher aka Stephen St Lawrence 1st Baron Howth -1430 [aged 69] died. His son Thomas [aged 18] succeeded 3rd Earl Howth, 3rd Viscount St Lawrence, 17th Baron Howth.