Sister of Tadeusz Andrzej Bonawentura Kos<bt,%20>ciuszko, an officer of engineers in the American army.

Daughter of Ludwik Tadeusz and Tekla (Ratomska) Kos<bt,%20>ciuszko. Married Piotr Estko; resided on an estate near Kobryn<bt,%20>, Poland. Lost touch with her brother in the early 1780s; repeatedly sought to contact him through Franklin and other intermediaries.

First letter in correspondence: December 19, 1783; James S. Pula, Thaddeus Kos<bt,%20>ciuszko: The Purest Son of Liberty (New York, 1999), pp. 22, 30-1, 211-12.