Baltinglass

Baltinglass, Co. Wicklow, is the birthplace most sources give for John Thomond O'Brien. Edmundo Murray's dictionary entry says he was born there in 1786, son of Martin O'Brien and Honoria O'Connor, and Tim Fanning's 2020 biography agrees. An older text held at Villanova, seen only in a search summary, gives Mallow, Co. Cork, and 1787.

O'Brien came to Buenos Aires in the 1810s as a merchant, then joined the army. He joined San Martín's Mounted Grenadiers in 1816, was made captain after Chacabuco and aide-de-camp to San Martín, fought at Cancha Rayada and Maipú and in the Peru campaign, and became a general in Peru in 1835. Fanning adds that he launched a ship on Lake Titicaca and organised Irish support in Buenos Aires for O'Connell's Catholic Emancipation campaign.

In the late 1820s Buenos Aires figures commissioned him to recruit Irish emigrants. After two years in Ireland he had little success, but he met John Mooney of Streamstown, whose emigration is described as the start of Irish migration from the Westmeath, Longford and Offaly area. Rosas later imprisoned him, and he was freed after pleas from Rosas's daughter and British diplomatic pressure. He died in Lisbon on 1 June 1861 on his way back to South America. His remains were brought to Argentina in 1938 with an official funeral and moved in January 2017 to the Campo Histórico El Plumerillo in Mendoza for the bicentenary of the Crossing of the Andes. A town in Bragado partido bears his name. The research records no memorial in Baltinglass.