here are some of the other Briscoe entries from 1846 for ref :
STANDARD (life), John Briscoe, Main street - FIRE, &c. OFFICE AGENTS.
Edward Briscoe (Grocer and provision merchant).
Edward Briscoe , Main st - Ironmongers & Hardwaremen
John Briscoe, Main st - Tanner & Currier
John Briscoe, discount office, and baronycess collector, Main street.
all - Bannagher, Offaly (Kings Co.)
John William Briscoe (and commissioner for taking affidavits), Charleville
terrace - ATTORNEYS.
Tullamore, Offaly (Kings Co.)
and only two others out side Dublin...
Patrick Briscoe, Main st - CLOTHES DEALERS
Ballinasloe, Co. Roscommon
John Briscoe , Catherine st, Waterford - Physicians & Surgeons
a surname distribution I have using Griffiths data (1847 to 1864) shows a concentration around Offaly & Kilkenny...
1. Offaly 16
2. Kilkenny 11
3. Cork 8
4. Dublin 6
5. Galway 4
6. Meath 4
7. Westmeath 4
Shane